I think some people are just naturally bitchy and when they talk to other people (on the computer 或者 in person) and theyre bitchy, it makes the people theyre talking to bitchy then the cycle continues and everyone gets bitchy. But thats just my opinion :)
No. It's people who are mean, end up getting reported and getting their accounts deleted, and make another one so it seems like there are a ton. Oh, and they usually have their mean families and 老友记 come on too.