I have been formulating a theory on that. I think some people hyped themselves soo much that when the beta didn't live up to their personal hyped view, they want to vent. Then there are the true "Trolls." They exist on every comment based medium on the web. And I'm not sure if it is one particular or several different disorders, so I guess I'd diagnose them as personality disorder NOS. But most of them are most likely people that suffer from borderline personality disorder. Meaning that they need to be the center of attention at all times. Sadly, this is usually accompanied by some type of self harm. Cutting, burning, or picking fights, in order for them to get the attention their brains crave. So if trolling on the internet helps them deal with this, at least self mutilation isn't evolved.