Tor-Server-Betreiber stellt nach Razzia Anonymisierungsserver ab - the biggest danger when using Tor or similar techniques: the technical ignorance of the authorities. They simply don't know what the stuff is and how they should react (taking the tor server would not have helped either, but would at least be logically justifiable). And of course the possibility for the authorities to intimidate people into stopping - which I do not want to imply here, I really just see the ignorance of the deciding official here. Tor is just exotic. For operators of such systems, however, this is part of the necessary risk assessment - you often and "gladly" encounter ignorance.