I don't have asperger's or anything, but I haven't noticed too much bitterness from what I've seen/read anymore than anyone else is about anything. Maybe I just don't notice it, because another forum I go to beats this one about a mile in bitter talk. I mean anyone can be a little bitter about anything and people will tend to I guess "cheer on" for lack of a better word, what ever it is that is similar to them. People will also talk down and generalize about things that were bothering them. Some few are quite lost in it and serious, but overall I think others are just venting and don't mean anything too harshly by it. I see it as just sharing disadvantages/ideas with people that may have a similar view of things.
People who are NT do the same thing about what they do/like, it just may not be as noticeable sometimes... or maybe if your different than they are you don't notice, because in your head your thinking what ever it is that they think makes them better is actually rather silly. Either that or when they are talking up something, they are more cheerful, while keeping their unhappiness/bitterness more hidden, so you don't get to hear them talk bitterly about stuff.
Also people are prone to want to be near people more like them, nothing bad about that, but it's good to stay open minded about different types of people.. you never know who could end up being pretty neat.