"Would AI porn reduce child abuse?"

The answer to that would be yes.

I honestly don't think this is an interesting question for a number of reasons.

A better question is whether AI panic would lead to incursions on free expression, privacy, due process, and other human rights. The answer to that is absolutely yes.

Prohibitions or restrictions tend not to be particularly nuanced. This is particularly the case when it involves the State. For a number of reasons, the State is the worst place for that.

The State also tends to be very adversarial, and not particularly co-operative (to advance better ends), whenever they get involved in something. Keeping the State out entirely seems like a good scenario.

Some arguments are very bad.

Someone might deliberately "send porn to a minor". It appears there are already laws to deal with this? Also, they could still bother a minor in different ways, and chances are that a bad actor could still do it, regardless of how someone targets good actors.

There are other ways in which someone could be harassing. However, these are either illegal, and / or don't inherently involve a particular technology. Also, punishing good actors would not stop bad ones.