[newaccount74]

Here's a different take:

Criminals and fraudsters will abuse pretty much every technology they can get their hands on. As a consequence, every service operator needs to do their part to prevent fraud and abuse. If you offer a service anonymously and indiscriminately, your service will be overrun by crooks, and you'll end up serving criminals.

The fact that your service could be used to defend free speech does not absolve you from your duty of monitoring the use of your service. If you realise your service is used for exchanging illegal content and bomb threats, it's your duty to do something against that, or stop providing the service.