Obviously that's a hard question with no perfect solution. That being said, I don't think _talking_ about something should be illegal. You and I talking about how to assassinate someone shouldn't be enough to put us away for years. Doing something or attempting to do something is where I draw the line.

Now, of course, I see the problem of letting people freely talk about killing people, overthrowing the government or running concentration camps. But forbidding this kind of speech is not going to prevent it if the pull is strong enough; even worse, it's going to strengthen their narrative about oppression. Instead, it should be possible to openly discuss why this is wrong. To understand why someone has an opinion and showing him why that trade-off is not worth it is far better than trying to forbid even thinking about it.

Now, I know that our action prevention might need some form of surveillance to prevent radical groups from taking actions and, at its worst, might fail to prevent some unnecessary violence. In my opinion, though, we can have much more freedom and maybe even prevent more people from radicalizing than by trying to censor wrong thoughts.