No way I'm taking on a lawyer, I didn't even go to college, but I do think you have to use common sense in what is the difference between a family picture of a baby in a bathtub compared to a line of naked preteen boys bent over with their bottoms to the camera. I don't think all nudity will become evidence of molestation, if common sense were used.
But I know, we aren't talking about right and wrong here, we're talking about the law.
But that's not how the law works. Because the prosecutor sees his job as "getting that conviction", once any nudity becomes admissible it will ALL become admissible.
The logical thing to me seems to be to allow nudity if it can be tied in some way to the specific act. If the complaining witness in this case had been able to identify specific pictures or books that were shown to him, that would be a sensible and logical rule.