Statistically you're right; as child porn became illegal and with heavier punishments rapes have went up. It used to, not even a few decades ago, be in playboy magazines and really easy to find.
That's obviously changed and you need some knowledge if you're into that, but unless you're a good little pedophile and don't want to hurt kids, then there's really no reason to beat it when you can do the real deal for no more risk if caught.

Infiltration is no longer possible as I just posted in my comment; to become admin on child porn sites they're now requiring you to make a video or pictures of you with your username and timestamp of you molesting/sexing a child.
You can't infiltrate that, not legally.