@Oliver If you came here expecting the typical 'antisocial nerds that are awkward, cringy and strange' then you're probably 90% correct, but that doesn't mean that they're not people with standards.
Fact of the matter is, whether you are a 20 year alpha-male jock figure with an ego the size of Saturn and a foul mouth to go with it, or if you are a 34 year old woman with 2 kids, a desk job and a lack of social interaction in the real world, or you are some being anywhere in between 'cool' and 'not cool' or you are some person that doesn't really care,
in the end you're going to want to get the same thing out of a social bond as anyone else and that is social gratification. If I am friends with you, that means I am getting something out of you - dark and cruel as that may sound it's true for any one friendship. I am putting time and effort into a friendship, and expect something back. If you pay for my food often, I'll be your friend, because I'm getting something out of you that outweighs the trouble of being your friend. BUT it can also be something as simple as 'being nice to you gives me a good feeling, and you're pleasant to be around' which is also a gain for me, if I felt that way.
Now the question you posed in here originally related to roleplaying and I answered it as such; you shouldn't have to dumb yourself down
if you're here solely to roleplay. As I am, I am not here to make friends, get along with people or even 'be nice' to anyone. I am here to roleplay. So, I don't dumb myself down and act as I would in the real world. That means that the few lasting friendships I made on here are built on me being a jackass, among other things, but at least I can say they're good/nice friendships because I don't have to fake anything.
If you're here to make friends and change yourself then yes, you'll have to dumb yourself down OOCly, and possibly try and figure out what it is that makes people like and/or dislike you so you can get a better grip on yourself as a person.
But that is something I myself struggle with, that people twice your age struggle with, and that by no means is something easily accomplished. It requires months, years and decades of retrospective insight that you're not going to have at 13 years old. I'm sorry. It's a progress that not everyone can accomplish and a progress that few, and dare I say, nobody, will ever completely master. Self-criticism is extremely hard and even if you can criticize yourself it's even harder to actually change yourself as a person.
But that is not related to roleplaying, or even to this website - that is related to the social standard that people expect and that's not something you should get help with on this site because like mentioned before, I think that a large part of this forum are people that struggle with the real world. Whether that is people who don't feel accepted, people who just aren't social, people who struggle with anxiety, mental disorders or anything.. these people tend to go here, I can agree with you on that. Not everyone here is like that, but large parts are.
Roleplaying is a great way to escape reality, but reality always comes first. Writing a nice story here about how your character slays a dragon isn't going to help you in the long run. Escapism is as dangerous as ignoring your problems.
Something entirely unrelated, but something that might help you with 'picking fights' is this; often it doesn't matter what you're saying but how you bring it. If I make a post and it contradicts your earlier post, think to yourself what is the best way to approach me/this other person? Instead of getting angry at them for ignoring you, maybe you could just.. point it out, add a smiley face, be nice about it.
It doesn't matter what you're saying. You could be advocating genocide. It's about the delivery. Always. So when you write a post, OOCly, keep that in mind, and think about how you're delivering a message. If you care about what people think of you, that is.