Hard to say. I generally agree with what you’ve said though. Also, lots of people have other fantasies that they would never enact in real life for various reasons (e.g. it’s unsafe, illegal, or both; edit: I should also absolutely list non-consensual here). I feel like pedophilia isn’t necessarily different.
However part of the reason loli/whatever is also illegal to distribute (it is, right? I assume it is at least somewhere) is that otherwise it helps people facilitate/organize distribution of real CSAM, which increases demand for it. That’s what I’ve heard at least and it makes sense to me. And I feel like that would apply to AI generated as well.