Your claim that it’s victimless is, of course, false since real children are used in the training data without consent.

Your assumption, but there are a ton of royalty-free images that contain children out there, more than enough for an AI to ‘learn’ proportions etc. Combine with adult nudity, and a generative AI can ‘bridge the gap’ create images of people that don’t exist (hence the word “generative”).

This also ignores the fact that the result is child porn

That’s not a fact. “Child porn” requires a child–pixels on a screen depicting the likeness of a person, and a person that does not actually exist in the real world to boot, is not a child.

Lastly, your claim that any of this results in any reduction in child abuse is spurious and unsubstantiated.

I’m just making a reasonable guess based on what’s been found about other things in the same subcategory (Japanese research found that those who have actually molested a kid were less likely to have consumed porn comics depicting that subject matter, than the general population), and in other sex categories, like how the prevalence of rape fantasy porn online correlates with a massive reduction of real-life rape.

Seems pretty unlikely that this is going to be the one and only exception to date where a fictional facsimile doesn’t ‘satiate’ the urge to offend in real life, and instead encourages the ‘consumer’ to offend.