If Tor is to succeed, the child pornographer must also be protected. Yes, I know this is abhorrent, but you cannot have a service that purports to protect you from the prying eyes of your government (or anyone else) while also being vulnerable to exploits like this one. You may be okay with the government collecting a series of such exploits and deploying them on child porn sites in similar fashion (many people are), but then there's nothing stopping them from using the same techniques to go after people buying drugs, expressing dissent, or simply holding political or social opinions that the government wishes to squash for whatever current reason. At that point, Tor is as good as dead.
