Why Do Gamers Hate Facebook?

So there has been a little question that has been buzzing around in my head for a while now. "Why do gamers hate Facebook?" is the question i constantly find myself pondering. I think the answer to this question has a variety of aspects to it, with the first part being that gamer's already have a social network. Forums are the backbone of social networking, they offer a lot of the same aspects of a "Facebook" or "Twitter" but with one key feature, Anonymity. On forums and on the web the user is, for the most part, completely anonymous, so what they say does not reflect upon them, simply the persona that they create. When you think about it, Facebook is just a giant forum system with some extra features thrown in, Facebook is used to talk to your friends about similar interests. So am i missing anything or is there another reason for why gamers hate Facebook?