He was depressive and he joined a chatroom which was all about insulting other people just to give him the final push.
+1 Bjorn, I think the guy joined an 'insult' chatroom just to push himself over the edge - can't blame the other users for the so called 'egging on', the chatroom was all about insulting each other - thats exactly what they were doing. I doubt anybody actually thought he'd do it.
TSC.