There are a lot of seedy,sick & deranged people in this world and I imagine they all have to get together somewhere.They sure aren't going to meet up and chat,share ideas,share pics or do anything illegal on Facebook running cyberghost.
The deep,dark,underground,or whatever you want to call it, web is full of pedophiles,rapists,sexual deviants of all flavors and a place to get anything you want.If you don't think it exists talk to someone in law enforcement who trolls there.Just like the surface web there are those there scamming and duping people also.
If you have to go there for anonymity or out of paranoia that big brother is out to get you have at it but I will take my chances that the FBI,NSA or whoever could care less what I an doing on the surface web.