I just browsed the hidden wiki in detail for the first time and I came across a site called "the human experiment" which deeply saddened me. Its a site set up by a small group of people including nurses, doctors and medical students to document their experiments. Basically they kidnap homeless people, keep them in a warehouse and perform horrible medical experiments on them until they die. The motto of the website is "not all humans are equal, some humans are born superior". God, what I would do to these people if I got my hands on them. As if homeless people don't have it bad enough as it is.
The very purpose of the tor network is to secure anonymity but many of the people who use tor (including these soulless scum who do these experiments) are not exceptionally computer savvy and I'm fairly sure any skilled hacker could uncover their identity somehow. It could probably even be done in an entirely legal manner through various social engineering techniques. If not, then I can't really think of a better reason to break the law than putting an end to the activities of psychopaths like these, and saving hundreds of people from suffering horribly.