Humans can become monsters.
Nazism and fascism metastasize in open societies. If they have a forum, if they're allowed to congregate online or in real life, they self-radicalize.
I'm extremely pro-free-speech, often to a fault -- but that doesn't apply to actual Nazis or other people who promote hate and violence.
This is really toxic shit and can be impossible to control once it gets going.
So you're an hypocrite.
If you believe in freedom.of speech you should seek to protect these minority voices that are being silenced by violence, you shouldn't be protecting people making death threats.
But the problem is saying that Nazis, without violence and threats of violence can silenced. And if you silenced people even before the threats, how can you say you're for the freedom of speech?
It's giving them an easily accessible echo chamber that radicalizes them and allows them to recruit. The internet has changed everything.
I'm not sure there is one best solution. We need to give bigots a chance to change their views, and we also need to protect their victims and potential victims, and those things are sometimes mutually exclusive.