There is some part of me that can rationalize that an AI is not a child and therefore there is no child abuse happening in the interaction, but that tiny part of my brain is shouted down immediately by the rest of my brain screaming, "PEOPLE ARE HORRIBLE. YOU CANNOT GIVE THEM THE OPPORTUNITY TO FANTASIZE ABOUT CSA IN A COMMUNITY AS PEOPLE WILL INEXORABLY ESCALATE INTO REAL LIFE CSA!"

Even if there are people who can indulge in imaginary CSAM without ever bringing it into real life, those are not the people you can set the bar against.

You have to set it against the average person and deduce from there what percentage of them when given free access to this material would be tempted into committing crimes. If that number goes up, your rule is too loose.

Giving everyone unlimited access to this without judgement will almost certainly increase child sex crimes. Therefore it must be restricted.