Smith must have hated Superman: The Movie, then. Because that film pitted a superhuman alien against a real-estate scam artist. And I'm sure Smith regards it as one of the greatest comic book films of all time.
In other words, this is yet another instance of Smith talking out of both sides of his mouth. I was at a convention once where someone asked Smith about some lawsuit against Burton. Smith explained that a reporter had asked him if he felt Burton's ending from Planet of the Apes was a rip-off from a similar scene in the Jay & Silent Bob comic and Smith jokingly replied that he's thinking of consulting a lawyer. Smith said it got back to Burton who said he didn't rip-off Smith's comic because Burton doesn't read comics. Smith then quipped, "which explains Batman." Yet Smith also counts Batman as one of his favorite comic book movies.
Kevin Smith is just a comic fan who makes comedies. That's it. He's not a sci-fi director. He's never directed a Superman film, he's never written a Superman comic book, and his only association with the character is writing a screenplay that was filed in the circular cabinet. So I fail to see why his opinion of Superman Returns matters.
In fact, I think we should instead look at the opinion of Richard Donner. Y'know, the guy who actually made Superman: The Movie and set a standard for comic book movies, so much so that his comic book film is still regarded as one of the best, even almost thirty years later and despite how dated Superman: The Movie is. And Donner? He loved Superman Returns.
So it occurs to me that Donner's opinion holds slightly more weight than a comic fan who makes stoner comedies.