The typical way of dealing with "bad people" is to subject them to the criminal justice system (or vigilantism if the problem is bad enough and the criminal justice system is inadequate). This tends to reduce, but not eliminate, the misbehaving.

Improving the ability to track down and prosecute perpetrators tends to result in less anonymity/privacy, so that makes the problem challenging.

Thinking in the long/very-long term, we need to get more innovative with the underlying technology to mitigate abuse. I mentioned this effort https://named-data.net in another part of the thread.