Well, I think given his output, what he says publicly has to be taken with a grain of salt, really. Besides, it's hardly uncommon knowledge he has an unusual sense of humour - I remember during the break week following the finishing of the third volume of FreakAngels, he was taking the piss out of the people who perhaps thought they were stealing a print-only book when they downloaded torrents and whatnot.
So I'd say at best, he's sceptical of superheroes, but it's clear he has a massive amount of respect for the characters and the medium, unlike, say, Ennis.