One other point

Where is the punishment in not allowing people to view abusive images, particularly when it affects those depicted in ways far more devastating than any casual viewer.

The punishment comes from the fact that you are forbidding something from all people on the basis of what some of them might do in the future. Transfer that to any other context and you can see why it is special pleading. Let's say . . . beating rugs. If you forbade the beating of rugs because some unknown person(s) at some undetermined point(s) in the future might get the wrong idea and beat other persons to death, then you are curtailing a right of all people to beat rungs on the basis of the abuse of that right by a handful of people in the future. Or let's use something both broader and more relevant: art. If you forbade all people from seeing art because some people might at some point be influenced by something in an artwork to commit a crime, then you are treating everyone as de facto criminals of a sort.