This is definitely an interesting issue. The points that matter to me when I look at it are these: A man who would, if he could, have sex with children is in jail. Good. But wait, what does 'would if he could' really mean. Does it mean that at some time, if the police hadn't entrapped this guy, he would have committed rape against a child, or was it that he had sexual fantasies about children that he would never have acted on in a real world situation because the sting was intentionally structured in such a fashion as to overcome the kinds on natural inhibitions that pertain in practically every real world situation. We cannot, from the article, answer this question because the details of how he was entrapped are not made available.
The only thing that prevents almost anybody from being able to be manipulated, given a sufficiently skilled manipulator, in such a way as to commit a crime is powerful internal ethical code rooted in a solid sense of self love. Such people are very rare.
It would seem to me then that this is an example of one of those conflicting rights issues where you have to sort of feel your way to decide which right has the greater precident. It seems too, that the issue is easier to resolve if the entrappment is regulated in such a way as not to cross the boundry into active manipulation, but allowing the victim to lead the way. Such matters are understood as for example in not leading a witness. In short, what needs to be on trial, I think, would be tape and video evidence of the actual takedown.
An important additional issue here, I think, is the fact that child sex crimes are not something that people ordinarily want to get caught at. Knowledge that such people are being actively hunted ought, one would thing, to raise the bar of inhibition. That can't be too bad.
The other thing that I find interesting about this is that I would feel completely different, I think, if this were about, say, smoking pot or taking acid, etc. I think that the intent to chemically alter consciousness is intergal to the human experience and has been for thousands and thousands of years. It may even be the origin of religion. To entrap somebody for doing something that is artificially illegal is very troublesome. Child rape strikes me as a completely different animal. Is that my prejudice? It's an interesting question. I don't think it is. How does one prove that.
Clearly the law is the law is the law is the solution for the simple minded, or this is what my relivious book says, but to distinguish your own since of objective reality from the nutcase next door who is equally certain and certifiably nuts isn't easy. I will yield to he who has the greater love. Pray that I can tell.