That guy wasn't the only victim. Remember
http://www.morrissey-solo.com/article.pl?sid=05/06/07/0413228
Looks like he's often on haughty horrible mode. You can find that hilarious...until it happens to you.
I think he's unpleasant (sorry, hilarious) only with people he feels could challenge him in some way, meaning, liking his work but still capable of independent thought and creativity.
If it's just to test them, he's always the one ending up looking silly, so I don't see why he bothers...Does it ever work? Who ever indulges him? How exactly do you keep the conversation going after he says stuff like that? Not everyone has the social skills of a Jehovah witness or the reflexes of a doormat.
I'm just surprised he never got punched. So is he, I guess.