I think a lot of the pushback that he’s getting from it is mostly to do with the level of snobbery that it was said with.
It’s incorrect anyway, because by what metric are movies judged other than revenue? He might as well have said that book adaptations don’t count either because they’re not original works.
It’s just a bizarre thing to have commented on, what was the point? If he makes a movie and it’s good, and it’s not as if he’s bitter because he’s made plenty of good movies, people will watch it. There was no reason to have a go at Marvel. If you want crap superhero movies look at DC stuff.