It does? I have never seen this, except in casual places that wrap the silverware in a napkin with a piece of paper tape and place it wherever. In a formal setting, the silverware is set so one works from the outside in, with utensils deemed necessary for dessert placed at the top.
Does it? I’m not familiar with that.
You just weren’t paying attention at the right moment. Or, everyone you have watched were using the side of the fork (in their right hand) to cut their food up.
Or maybe I just hang around with a lower class of people 
No, you are wrong. Forks on the left, knives on the right, and you work your way outside to in with each course. The only time all the cutlery would be on the same side would be if Outback Steakhouse did a prix fixe chefs tasting menu night.
http://www.emilypost.com/everyday-manners/table-manners/372-formal-place-setting
No one taught me how to use the utensils, either, and I’m ambidextrous, so I use them in hand they start in. Fork in the left, knife in the right, and they stay there. I sometimes hold the fork facing up, and sometimes down, probably the same as zoid, but I’ve never thought about it much.
I have sometimes seen people switch hands to always use the dominant hand for the more important thing they are holding. It seems awkward to me, but I can’t say I’ve ever cared deeply about how other people hold utensils.
I agree that formal places put utensils on both sides, and it’s only casual restaurants that put them all together.
Anyway, to answer the OP, because the knife has always been in the right, since most people are right handed, and the knife was used in European dining for centuries before the fork was invented. As a latecomer, it got the other spot, since you were already using your right hand to hold the knife.
Heh, well you and me both.
Oh, wait… 
Hm. Utter brain lock I guess. Thanks.
If you’re eating something that doesn’t require cutting with a knife, it seems easier to just keep your fork in your dominant (= right, for most people) hand. My WAG is that the “American style” developed among people who ate knifeless food often enough that, when they did eat food that required a knife, it still felt more natural to transfer bites of food to one’s mouth with one’s fork in one’s right hand.
diner discussions often went to politics and religion, things often got heated. by having the fork on the left it was an obvious movement, this gave neighboring people a chance to move out of the way.
It’s amazing to me reading about whether the fork typically stays in the left hand or switches back and forth, described as the UK and American styles, respectively. I’ve never in my life done either. I’m right-handed, and the fork stays in my right hand. If I have to cut something I do it with the knife in my left. Surely I’m not alone in this perfectly logical habit! The only time I have a fork in my left hand and a knife in my right is when those are carving utensils and I’m doing some serious carving on a gigantic roast!
Emily Post would probably be horrified but them’s the breaks! 
I haven’t seen it either, but as chiroptera said, I probably missed the moment as well. I eat and cut with either hand and might switch hands and tasks several times during a meal. I’ve never had anyone point out that it was wrong to eat that way. As long as the food is getting into my mouth, why should it matter?
It really is pretty common. I grew up eating European style, and it never made sense to me to do it any other way, but I do see people doing it the cut &switch hands method regularly enough. Like they’ll cut up their steak with knife right, fork left, switch fork to right hand to pick up and eat. Or they will precut everything and then switch fork to the right hand. I don’t see it so much in my neighborhood clan of people (we mostly grew up with Eastern European roots where we don’t switch hands), but I do notice it outside the neighborhood.
For example, I went to Youtube and typed “eating steak.” This is the first one I clicked on. The first bite he takes with the fork in his left hand but notice how he switches for the rest. That’s what I often see.
From Slate.com:
Probably because I don’t pay any attention to them, nor do I care how they eat. I grew up eating “Euro style”, as did everyone else in my family, and as did all of my kids. Changing hands is a ridiculous, awkward custom, but if that’s what makes you (generic) feel especially American, then have at it.
Agreed! Another advantage of eating “Euro style” is that you can use the knife (in your right hand) to move food items over the top of the “main” food item being held by the fork. For example, with the fork holding down a piece of steak, I can balance the potato/rice/veggie between the steak and the curved end of the fork. Doing this using the “American style” with the tines up is trickier and much less elegant.
I’m an American and I hold the fork in my right hand and cut with the knife in my left. I am right handed. I’ve tried it the other way around, and I can’t do the cutting with my right hand, nor can I get the fork to my mouth while holding it in my left hand! It just seems so crazy backwards.
Of course! As I said, this is how a right-handed person would carve a roast, and also more or less how you’d set yourself up to use the dominant hand to cut a log with a timber saw. But it amazes me that anyone would use this technique for cutting a steak.
Served a dish that doesn’t require cutting and given only a fork, I would expect that the fork would be held in the dominant hand, much as this is the hand that you write with. And if the food does require some minimal aid from a knife, either for cutting or helping the fork to scoop, I’d expect the knife to be in the alternate hand. Fork, right; knife, left (for right-handed persons). Anything else perplexes me. Perhaps I’m an alien from a distant planet.
ETA:
Hah! Either another logical person, or another Vulcan!
I think “awkward” is whatever you’re not used to doing.