He's a spoiled dumbstuff though. It's better if he doesn't get what he wants.
You'd have to be a complete moron not to ban this guy. He's an attention whore who is insulting everyone and asking to be banned. It is simply not worth keeping him around. There is also the possibility that his actual goal is to piss everyone off without getting banned through use of reverse psychology, in which case you're doing exactly what he wants.
You could also think of it in a more extreme scenario, for both logical and comedic purposes:
Bank robber: Hahaha, come on you stupid cops, shoot me! I dare you!
Cop 1: Alright, starfish, you asked for it!
Cop 2: No! We'd just be giving him what he wants!
