I think the idea in this case is that there isn't re-victimization. The point of these sting operations is to lead to less victims overall.
From all I have heard and read on the subject of sex crimes, the research and the government policy has nothing to do with each other. Worse, some feminist movements have successfully lobbied to prevent research on criminal sexual behavior, on the principle that deeming such behavior as abnormal will result in lower jail sentence for criminals.
Instead we have this abnormal-but-not-abnormal behavior happening "randomly" by totally "healthy" individuals, and there is very little to explain why it happens or how we can reduce it.
More research I think would go a long way.