As rare as actual child porn is, the government loves these cases because the defendant is considered guilty before even being arrested, certainly before he gets in front of a judge/jury and there's so much taboo around the issue that most people are unwilling to come to the aid of the defendant. Come to think of it, I could say the same thing about terrorism cases (which are even rarer). And yes, the message they're constantly sending is that pretty much the whole Bill of Rights has been repealed, not just the 5th.