It is 100% classless to sit around before class and insult other people in your section, by name, in their absence in front of a bunch of your classmates. If you want to have a private conversation in private and insult people, it's not okay, but it's sure better than having a private conversation in front of 20 other people who can perfectly well hear what you're saying. And by the way, many of them are trying to study while you're chatting. Like right now, I'm hearing you insulting blogs in general as being stupid. Well, guess what? You just made it on a blog! Congratulations!
I have a pretty high tolerance for annoying behavior, but I have a very low tolerance for mean behavior.