Wait 'til you hear who invented it...

That said, considering how many illegal services continue to run on it, I don't think it's as porous as some make it out. Definitely has well-documented weaknesses but the project maintainers tend to address them fairly straightforward.

Of course, you're also just as likely to be buying drugs off an Onion market that the FBI seized and kept running just to catch more bad guys, despite it also hosting illegal content itself.