He must be prosecuted on the basis of Platonic principles. Otherwise, the law is meaningless. However, the obvious consideration means that if convicted, he would not receive substantial punishment.
I do find it fascinating that over in the sex worker thread, TNF is saying we should stop putting sex on a weird pedestal, yet here he clearly recognizes that touching a child's sexual areas is a lot different than touching a child's other areas. So clearly, there is something different about it.
TNF how do you defend consensual sex while condemning rape?