That is exactly my sentimonies.
Sounds like some really nice people tried to initiate a conversation with you because they thought you might need a friend. Even if that assumption was wrong, their hearts were in the right place.
They made a mistake in judgment, but it was kindly meant.
If anyone is being judgmental here, it’s you.
I’m usually alone when I eat out. I don’t know if others notice I’m alone or are judging me or not. That’s because I always bring my Nook HD+ with me, so I’m reading. But eating out in the real world is different than in an on-campus cafeteria, as a campus is sort of a community. So, yeah, they’re probably judging you if you’re eating alone. They’re talking about what you’re wearing, your hair, your tats and piercings or lack thereof, whom you’re dating or not dating, what you’re eating, etc.
There’s a difference between being alone and being lonely.
If you see someone staring at you, stare directly back at them and don’t flinch.
Unless it’s a girl, then you go talk to her.
Who cares?
Some will judge, others won’t. The person sitting alone either cares or doesn’t care. If they care, they’re being foolish.
In any case, it’s a silly waste of a great opportunity, but that’s just MHO.
I agree with the last sentence (There’s a Greta Garbo quote, “I never said, ‘I want to be alone.’ I only said, ‘I want to be left alone.’ There is all the difference.”), but I think your first paragraph would be more accurate if we were discussing sitting alone in a high school cafeteria, not a college one.
Unless this is an incredibly small campus where everyone knows each other, I don’t see how anyone could find it odd for someone to grab a snack in between classes and catch up on work or reading while sitting by themselves. I also don’t see how anyone eating alone on a regular basis could consistently be noticed, due to the large amount of people in the cafeteria, different eating times, etc. Plus, I would hope college students, especially older ones, would have the maturity to not care about someone eating alone much less all the other stuff you mentioned.
That said, I went to a school in an urban area with 10,000+ students (small compared to large state schools with 40,000+ students- I don’t see how anyone dining alone could be noticed there!) so YMMV.
I went to a big campus too. Not only were there multiple dining halls to choose from, but we also had a big food court. So it would be hard to always bump into the same “loner” individual at each meal every day.
But it’s not inconceivable that a person would be noticed after a long enough period of time (say a semester). Especially if there is something about that person that makes them stand out. Like, perhaps them always being alone.
Whether there is judgment involves depend on other factors. I’m guessing if the loner doesn’t appear eccentric or creepy, then “observers” won’t think much of anything. But if he gives off creepy or weirdo vibes, then him eating alone will only accentuate the creepy/weird vibes.
I ate alone about 80% of the time , I highly doubt anyone noticed and it would have been the last thing I noticed. Occasionally I’d eat with my roommate or a friend , mainly at dinner. Breakfast and lunch were usually me solo with a book or a newspaper. This was way before the smart phone era, so I enjoyed the 20 minutes with the school paper or a Wall Street journal. College eating areas, in my experience, aren’t like high school cafeterias. You don’t have every table packed except for the one loser table.
Or special needs people table! 
I usually ate alone when I lived in the dorms and I don’t think anyone paid much attention. I definitely didn’t pay much attention to anyone else in the cafeteria.
When I went back to grad school I was the king of alone. Barely made friends and had a relatively open schedule so eating alone was the norm for me.
Basically I never noticed or cared if someone else was eating alone. Frankly I liked it cuz that meant there were chairs available next to the other person eating alone. Not to mention in this day and age of laptops and cell phones I just ate and surfed the web and/or looked at Pinterest on my phone so I wasn’t starving for entertainment either.
(and when that got boring imagining the girls naked didn’t hurt either)
The rest of your advice is accurate, but this is an oversimplification. Look at the many, many threads we’ve had where complete strangers are judged by their banal behavior. Someone who walks on the left side of the street or stops walking for a second can be a horrible person.
There are people who will judge you, but their judgment is unimportant. Often even they know this, as they completely forget about it once they notice something else. There’s just nothing legitimately judge-worthy about sitting alone.
The real thing you need to realize is that such frivolous judgments are unlikely to affect your life. That’s what the spotlight effect really is. Sure, people don’t notice as much as you think they do. But what they do notice doesn’t matter as much as you think it does, either.
Nothing bad is going to happen to you if someone does notice you sit alone and thinks anything of it.
I wouldn’t worry about what people might think of you. I’d be more worried that you’re missing an opportunity to meet people and be social. I was never any good at making friends but I met a few guys in my freshman dorm and we ate dinner together most days. That kind of social interaction is huge and one of the best things about college.
Is there anyone in your hall/building/etc that you might have some shared interests with? You could ask them if they wanted to eat with you sometime.
Regarding breakfast and lunch, IME most people tended to eat by themselves because of class schedules and whatnot.
I totally agree with this. I know people think they are being helpful when they say “No one cares!” but the truth is that there is ALWAYS someone who cares. Maybe they shouldn’t care. Maybe they don’t even want to care. But there is always someone out there who notices other people’s abnormalities and flaws and quirks. The question isn’t whether these people exist. It’s what does it matter if they do.
Whenever I do something unusual in public and I’m feeling self-conscious about it, I imagine myself giving the finger to anyone who might be tempted to laugh at me. This attitude emboldens me. But telling myself that no one is paying attention just feels self-delusional.
If you always eat alone at the same time and the same location, people will probably notice and think you are a loner. This may affect interactions they have with you at other times.
If you eat at varied times, varied locations, and are always doing something like studying, people will not necessarily notice. And if they do, they will likely think you’re busy trying to get something done.
If you avoid other friends and acquaintances in the cafeteria to sit alone, they will likely think less of you. By avoiding them, you are saying they aren’t important to you, so they won’t make you as important.
I was an introvert in college who often ate alone if none of my small group of friends were available. It made me feel pretty lonely and reinforced the feeling that I didn’t fit in. I wish I had instead sat at a table near people that I knew from class. Pick a seat one or two seats away, ask if it was taken, and then pulled out a book and studied. That way I wouldn’t have stood out and perhaps I would have made more friends.
As an adult I don’t care. I enjoy eating alone rather than making small talk with co-workers. I have a satisfying life and don’t feel like I’m missing anything by being alone. But when I was in college, I wasn’t as self confident and being alone had a negative effect.