It's hard to grapple with the degree of the offense. It is offensive. Imagine a small village a couple hundred years ago with a central square and something like a bulletin board. Someone paints an explicit painting using a village youth's face an puts it on the bulletin board. That's going to create quite a stir, and maybe a lynch mob. I don't want to trivialize the offense.
That said, there's the question of where the line is drawn. If I clip from a biology textbook an image of a nude woman, and I clip the Gerber baby's head and paste it onto the nude woman's head, what is that? If I generate the face of a young boy, then draw a stick figure under it and give the stick figure a stick erection, what is that? I don't know. I mean these things are weird and offensive, but to what degree?