No, it's because it will likely lead to those consuming it turning to real life sexual abuse. The behavior says "I'm attracted to children." We have a lot of good data on where this precisely leads to when entirely unsupervised or unchecked.
> but kinda orthogonal to the whole "and also you get 20+ years in the locker" thing.
You've constantly created this strawman but it appears nowhere in my actual argument. To be clear it should be like DUIs, with small penalties on first time offenses increasing to much larger ones upon repetition of the crime.
> it's pretty much impossible to restrict this
Right. It's impossible to stop people committing murder as well. It's also impossible to catch every perpetrator. Yet we don't strain ourselves to have the laws on the books, and it's quite possible the laws, and the penalties themselves, have a "chilling effect" when it comes to criminality.
Or, if your sensibility of diminished rights is so offended, then it can be a trade. If you want to consume AI child pornography you have to voluntarily add your name to a public list. Those on this list will obviously be restricted from certain careers, certain public settings, and will be monitored when entering certain areas.
Which sounds more appropriate to you?