The only thing the forum needs is the fostering of higher standards of discourse, something that can't entirely be done through moderation because nobody's going to discuss anything if everyone is banned.
We can't just live in a delusional opinion vacuum where only right ideas are tolerated, but at the same time these drive-by negative posts should not be tolerated either. If you have something to say, back it up. This really goes for positive posts too, except nobody really gets riled up by "omg this game is so awesome." Context and understanding are important, and if you aren't going to really contribute to a discussion, to one side or another, you shouldn't be saying anything.