People are naturally more aggressive on the internet, because it allows them to talk via an alias. There are no real social consequences to actions taken here. Whereas in real life, you wouldn't insult your boss to his face for fear of losing your job, if you were to run into him on the internet, and were using an alias, you would happily call some an starfish, because he can't tell it was you who did so.
“We are Anonymous. We are Legion. We do not forgive. We do not forget. Expect us.”