I'm gonna play devil's advocate for a bit: King doesn't write copious amounts of child rape scenes because he's secretly into that, but merely because he's a hack who can't figure out other ways of shocking the reader and depicting a corrupting influence in other ways than "innocent child gets corrupted into sex". His content is awful by design, he's a horror writer after all, but he's also kinda bad at it and doesn't have much imagination.
Also, him writing himself as a God in Dark Tower is less self-aggrandizing than it sounds, the Dark Tower is basically his attempt at being meta, while also being entirely literal about it. The multiverse there is his collected literary works, and he thought it would be a good idea to include himself in it. At least he takes the piss out of himself in that.
Still sucks, though. I mean, I enjoyed his books as a kid and I really liked the Dark Tower, but growing older it just becomes too apparent how he's a rather unimaginative hack.