Many years ago (about 25) I read an article in a newspaper (idk the name, but it may have been the The Computer Paper, which is archived on line someplace}. This article noted that a study had been commissioned to show that cp access increases child abuse. The study seemed to show the opposite.
Here's the problem with even AI generated cp: It might lower abuse in the beginning, but with increased access it would 'normalise' the perception of such conduct. This would likely increase abuse over time, even involving persons who may not have been so inclined otherwise.
This is all a very complex. A solution isn't simple. Shunning things in anyway won't help though, and that seems to be the current most popular way to deal with the issue.
With regards to your last paragraph: Pedophiles can indeed by straight, gay or bi. Pedophiles may also not become molesters, and molesters of children may not at all be pedophilic. It's seems you understand this. I mentioned ITT that I read a newspaper article many years ago that was commissioned to show the access to cp would increase child abuse, it seemed to show the opposite.
If persons could use AI to generate their own porn of their own personal fantasies (whatever those might be) and NOT share that content what then? Canada allows this for text (maybe certain visuals? Audio? IDK). I don't know about current 'obscene' laws in the USA, however, I do recall reading about an art exhibit in NY which featured an upside down urinal that was deemed obscene, than later deemed a work or art. I also recall seeing (via an internet image) a sculpture of what seemed to be a circle of children with penises as noses. Porn? Art? Comedy?