"I tried to meet new people at hobbies and dance lessons, but guess what - they're all full of lonely developers and other socially awkward people - short guys looking for girlfriends, unattractive/aging women looking for husbands, etc."

Gee, I'm just shocked that you're having a difficult time making friends. Who wouldn't want to be friends with judgemental folks?

There isn't anything to mention that you don't know already. There is no quick fix. Find a hobby like sports or music etc and meet people through that, or do other sorts of meetups. But the problem here is your attitude, not the people. Don't take your frustrations out on other people, it's not cool.