At the same time, we are equally certain that sexual fantasies are morally neutral. Indeed, no one (except perhaps some hard-core Catholics) would have blamed Ewing for creating pornographic pictures of QTCinderella in his mind.

I don’t think this is true. Sexually fantasies aren’t morally neutral. If a fucked up stalker fantasizes about raping and killing a celebrity, that’s certainly not “morally neutral”. And we’d certainly blame such a person for creating those fantasies in their mind.

And we certainly do blame people who stand around children’s playgrounds and watch the kids there with more than a parents interest.