Because most men have male friends, unrelated to business, whom they enjoy socializing with. You apparently don’t.
[1. Does it exist? Most certainly
2. Are men aware of it? This man is, as are my close friends
3. How does it manifest? As kunilou said, “He’s got my back” is a great way to put it. When you need something, those who really care are there (and vice versa). On rare occasion, one of my friends or I will say it (the sober “I love you, man”), but it really doesn’t need to be said to be understood.
4. Do you always keep it hidden? I’m not inclined to talk about my emotions often, but I don’t keep it hidden. There’s plenty of room between demonstrative and hidden.
5. If you keep it hidden, have you ever regretted not showing it? n/a
6. If you don’t keep it hidden have you ever regretted showing it? And I’m not talking about a drunken “I love you man”. Nope. No regrets, even in cases where the expression of sentiment has been the most explicit.
7. If you show it, how do you show it? Gestures? Actions? Words? Actions, mostly. I think the best example of this is when a close friend of mine was losing his kidneys to a genetic disorder. No family kidneys were available for donation because his brother has the same disorder and had already gotten the 2 available family transplants. A couple dozen of his friends, male and female, volunteered ourselves as potential donors and got organized to go through the process of figuring out who was the most appropriate match. He now has a transplant (successful so far, knock wood) and a bench of backup donors waiting in the wings in case of rejection.
Oh, and Least Original User Name Ever’s post reminded me of one of my favorite quotes on friendship. “Friends help you move. True friends help you move bodies.”
OK, then you are correct.
But to be fair, I don’t really have female “friends” either. If I want to spend time with a female, I ultimately want a relationship more intimate than what most would consider as “just friends”.
I guess I’m just not a friends type of guy.
I gave this a lot of thought before posting in this thread, but I’m pretty sure I don’t love any men, either, and I never have. All of people who have ever treated me badly, assaulted me, stolen my property, screwed me out of a job or a place to live were men. On the whole, I don’t trust men. I like a few of them. I like one of them enough to have him in my house and socialize with my wife, because he is, as far as I can tell, one of the good ones. He doesn’t come with an agenda. I consider myself lucky to know someone like that. He does stuff for me. I do stuff for him. But if one of us were to say “I love you, man,” it’d get all weird.
1. Does it exist?
As certainly as any other kind of love does. In fact, to take a cue from When Harry Met Sally, it may even be more real than platonic love between members of opposite genders.
**2. Are men aware of it? **
Some are more comfortable with it than others, but I can’t think of any man I’ve known who was utterly oblivious or in complete denial of it.
**3. How does it manifest? **
I can really only speak of myself, my male family members and my male friends. My family was always big on hugs; my dad, the Utah redneck, college football player and two-tour Vietnam vet, still kissed me on the cheek when I would come home from college in the summer. I have four or five male friends whom I have no problems hugging, for example when we haven’t seen each other in a while, or for some other special occasion.
4. Do you always keep it hidden?
I’m guarded about it, but I have no problem being frank about my feelings with most people. I gravitate towards people who will allow me that; macho tough guys don’t tend to become my friends.
5. If you keep it hidden, have you ever regretted not showing it?
Never been an issue.
6. If you don’t keep it hidden have you ever regretted showing it? And I’m not talking about a drunken “I love you man”.
Drunken ILYMs can be an important first step. 
And there have been far more times I’ve regretted opening up to women in this manner than to men.
7. If you show it, how do you show it? Gestures? Actions? Words?
A combination of the three. I know it sounds like a copout answer, but it’s true.
That stereotype on how my people believing that all emotions should be expressed openly? It’s true. It’s also true that we love Chinese food and Barbra Streissand, but that’s not relevant here.
If I have not seen a close male friend for a while, we greet eachother with yells and bear hugs.(Many of my close friends are of Irish heritage and don’t believe in hiding their emotions either). We buy each other presents, not just for birthdays and holidays, but little things just to show affection. We arrange to do things together (Like watching the Underworld DVD at a friend’s house and then going to the theater to see Underworld-Evolution). We went camping for a friend’s birthday. I saw a rattlesnake. We met a very friendly park ranger (get yer mind’s out of the gutter. He was just a great guy, deeply committed to protecting the environment, and more concerned with everybody having a good time than filling out the proper forms in advance).
Jewish tradition teaches that only if I could not do these things should I feel shame.
Are we talking about Jewish people, or gayish people? 
Jewish. I don’t mean we give each other silver earings and a longstem rose. But, say one of my friends is renting a movie. In the bargain bin they spot Really Cheezy Zombie Movie 34. Knowing that I am a fan of such things, they pay $2 for this bit of cinema and give it to me the next time they see me. I may be passing through a dollar store and buy the gang a bunch of lightsabers.
How is that less than manly? What part of caring for my friends and being able to express it openly without shame is unmacho?
For the record-I say this for the benefit of any hot Dope women reading this thread, I am straight and single. But why should anything I’ve posted in this thread imply otherwise?
Heck, in “Some Kind of Monster”, Lars Ulrich complains that it once took James Hetfield getting a wicked drunk on to say, “I love you, man”. So he knew it was there, but seemed genuinely annoyed and even maybe hurt that it took that for James to actually say it.
You’re asking this question seriously? Not kidding at all?
Geez, of course. What, there aren’t fathers and sons who love each other? Brothers?
In my general circle of male friends hugging is limited to “glad you survived falling off Hoover Dam”. I could count the number of times I hugged my dad on 1 hand. Just not something we did. It fell into the category of “men don’t cry”. Mom got a couple of hugs now and then when she needed it.
Regardless of how close a friendship I’ve had with another man there has always been a general tradition of not expressing it in any manner.
Certainly there are, but there are many of them who have a really hard time expressing it, especially verbally. I have friends whose dads never hugged them. Dad would hug the girls in the family, but not the boys. If one of the boys was crying, Dad would send Mom to talk to them.
Boys aren’t supposed to cry anyway. 
Well, yes and no. At first the question was merely, “How do you manifest it, do you hide it, etc.” But after I talked to the first two guys, I thought I’d better expand the questions.
(But I do resent the second question. I hate the assumption that parents and children are always supposed to love each other. Sometimes the parents aren’t deserving of it. Abusive parents, for example.)
Anyway, the time is only recently that men were even encouraged to show their emotions. Not too long, we still had the very macho stereotype. Read biographies of people that grew up in the previous generation. You’ll see lots of incidents where the sons never did anything but shake their dad’s hand when they grew to manhood. Affection was frowned upon.
Thanks for all the responses guys. More what I expected, than those two freaks in the OP. 
But I still wonder if they felt weird about saying something that they might not have felt weirdly about writing down. Since then though I have talked to other men IRL who have been less concerned about hiding it and have answered more honestly it seems to me. Still, I am taking everybody’s answers at face value.
1. Does it exist?
Absolutely.
2. Are men aware of it?
Yes.
**
3. How does it manifest?**
I love/loved my Dad and he loved me. We would hug on birthdays and special ocasions without any embarassment. When I was fourteen, I went away on a weekend retreat, and the parents were supposed to write a letter to their kids about how they felt about their relationship. He wrote me a letter where he told me how much he loved me, how proud he was of me, and how he thanked God for me, and how he wanted to dedicate his life to helping me be happy and well. Needless to say, this kid was full out bawling with emotion for a couple of hours after reading it. He had this gesture of putting his hand on my shoulder and squeezing. Sometimes he would say: “When I do this, remember: it means I’m telling you I love you.”; mostly, he would just squeeze my shoulder whenever he went by, at home or elsewhere. I think he wanted a way to show me and tell me often without any sentimental dramatics that might embarass a teenage son. The last time I touched him was when I sqeezed his shoulder like that just before they closed his casket.
I have a best friend (in addition to my wife) who is a guy. I would say I love him more dearly than a brother, except I’ve seen some brothers who don’t care much for each other, so that wouldn’t be saying much. We’re always there for each other, no matter what. We help raise each other’s kids (his daughters are my goddaughters) we work out together, have each other’s families over for a big family dinner every second Sunday, do Bible study together. Our common Christianity is a big part of our bond; we’ve each strengthened each other’s faith each in our own different way: he’s big time into scripture and apologetics, and I’ve had many significant experiences that have deepened my faith. We can talk about anything and complement each other very well: he’s artistic, I’m scientific, he’s a wisecracking joker and I’m ever the straight man. We often hug goodbye, and say “I love you” with minimum fuss or embarassment. Tools, books and food flow freely between the houses.
4. Do you always keep it hidden?
We don’t make a big deal about it, but we don’t hide it either.
5. If you keep it hidden, have you ever regretted not showing it?
n/a
6. If you don’t keep it hidden have you ever regretted showing it? And I’m not talking about a drunken “I love you man”.
I’m grateful we can show it. It makes the retlationship stronger.
**
7. If you show it, how do you show it? Gestures? Actions? Words?**
Words, gifts, prayer, hugs, help in time of need (both big and small, material, emotional & spiritual), time spent, hand-me-downs, meals together, etc.
You’re talking about American society. But, if I look past Ward Cleaver, I see a long line of Tevyas. Seriously, going through all the folklore and tradition (No. I’m not gonna) I can’t find anything saying Jewish men should not express emotion. The closest I can get is one story about a town that disapproves of the rabbi’s habit of doing silly dances and waving a myrtle branch at wedding receptions. The moral of that story is that looking foolish is not important if you are bringing joy to people.
Magiver I cannot wrap my head around that. I don’t mean that as an insult. I honestly cannot understand the how or why.
Yes, I am talking about American society - and Indian, too. In different ways, men are encouraged to show some emotion but not tears or affection, really. But I have to be :o and admit I don’t know what Tevya is.
Tevya is the lead in Fiddler On The Roof. It’s a rather accurate portrayal of Jewish life in a Russian ghetto.
I wonder how long the the custom of men not expressing certain emotions goes back. Certainly, it was part of the fifties. But, the fifties were an odd blip in many other trends. Did the men of the twenties hug? What about the 1880s? Did George Washington hug Ben Franklin and say ‘I love you, Ben’? Did Franklin reply ‘You are a fine general and a great human being, and I love you as my brother. Regardless, you are not getting this tankard of ale.’?
There are many ways you can express your love for your children, DocCathode. My dad often worked sixty hour weeks, but what little free time he had he spent it with his family, and especially his sons. I remember evenings of him reading to us on his lap, or going golfing together, or to museums or shows or concerts. He wasn’t into hugging or kissing, but he did know what counted, and that was time that we got to spend together.