These cases are interesting tests of our first amendment rights. "Real" CP requires abuse of a minor, and I think we can all agree that it should be illegal. But it gets pretty messy when we are talking about depictions of abuse.
Currently, we do not outlaw written depictions nor drawings of child sexual abuse. In my opinion, we do not ban these things partly because they are obvious fictions. But also I think we recognize that we should not be in the business of criminalizing expression, regardless of how disgusting it is. I can imagine instances where these fictional depictions could be used in a way that is criminal, such as using them to blackmail someone. In the absence of any harm, it is difficult to justify criminalizing fictional depictions of child abuse.
So how are AI-generated depictions different? First, they are not obvious fictions. Is this enough to cross the line into criminal behavior? I think reasonable minds could disagree. Second, is there harm from these depictions? If the AI models were trained on abusive content, then yes there is harm directly tied to the generation of these images. But what if the training data did not include any abusive content, and these images really are purely depictions of imagination? Then the discussion of harms becomes pretty vague and indirect. Will these images embolden child abusers or increase demand for "real" images of abuse. Is that enough to criminalize them, or should they be treated like other fictional depictions?
We will have some very interesting case law around AI generated content and the limits of free speech. One could argue that the AI is not a person and has no right of free speech, so any content generated by AI could be regulated in any manner. But this argument fails to acknowledge that AI is a tool for expression, similar to pen and paper.
A big problem with AI content is that we have become accustomed to viewing photos and videos as trusted forms of truth. As we re-learn what forms of media can be trusted as "real," we will likely change our opinions about fringe forms of AI-generated content and where it is appropriate to regulate them.