CSAM possession is illegal because possession directly supports creation
To expound on this: prior to this point, the creation of CSAM requires that children be sexually exploited. You could not have CSAM without children being harmed. But what about when no direct harms have occurred? Is lolicon hentai ‘obscene’? Well, according to the law and case law, yes, but it’s not usually enforced. If we agree that drawings of children engaged in sexual acts aren’t causing direct harm–that is, children are not being sexually abused in order to create the drawings–then how much different is a computer-generated image that isn’t based off any specific person or event? It seem to me that, whether or not a pedophile might decide that they eventually want more than LLM-generated images is not relevant. Treating a future possibility as a foregone conclusion is exactly the rationale behind Reefer Madness and the idea of ‘gateway’ drugs.
Allow me to float a second possibility that will certainly be less popular.
Start with two premises: first, pedophilia is a characteristic that appears to be an orientation. That is, a true pedophile–a person exclusively sexually attracted to pre-pubescent children–does not choose to be a pedophile, any more than a person chooses to be gay. (My understanding is that very few pedophiles are exclusively pedophilic though, and that many child molesters are opportunistic sexual predators rather than being pedophiles.) Secondly, the rates of sexual assault appear to have . So the question I would have is, would wide availability of LLM-generated CSAM–CSAM that didn’t cause any real, direct harm to children–actually decrease rates of child sexual assault?