GOD.
There are seriously forums full of pedofiles sharing pictures and - maybe worse? - their stories and wisdoms. Maybe out of utter fascination, I spend about few hours on there and I felt like I want to murder all humanity. On one of these forums, there was this alleged "doctor", who adviced people, from what age you can have sex with your children without their doctor to notice. Tips how to kidnap young children. The worst thing was that I just knew that - if they don't do something stupid - they are basically untracable and uncatchable, while I would simply want to catch them all and kill them one by one. (I am sorry for being so expressive.)
There were also some picture forums but really I couldn't stand that, I just wanted to vomit while I was shaking.
I... am not sure why I am writing this. I am all for Tor. But we have to admit - when everything is allowed and anonymous, EVERYTHING is allowed and anonymous. And the dark parts of humanity flow on top. Drug markets, weapon markets, assasin markets (altough I don't know how sersiously to take those), terrorist websites, child porn websites.
But - as hard it is for me to say it - to see that the seriously f...d up child molesters are freely allowed to say really anything there and noone has a chance to catch them just shows that Tor is really anonymous and safe.
edit: I do not know if The Hidden Wiki is still operating, if the dark places I visited are still operating, it is about one year and I did not feel any urge to revisit it again.