We used to have to refer to historical material for that.
Now we can see it unfold in a sandbox.
If you are an historian, an economist, a psychologist or a sociologist, 4chan is something that deserves a look.
I mostly agree, however our methods of communication are fundamentally part of our social structures. I don't think they can be extricated from the actions that we take. If a website's infrastructure encourages and promotes extremist dialogue, that is, in of itself, part of the broken social structure.
> No amount of 4chan posts will cause a healthy person to become a violent extremist. And no amount of censorship can stop the rise of extremism.
I think this lacks nuance. 4chan absolutely won't take a healthy person to an extremist. But extremist content absolutely takes mildly unhealthy people and 1) radicalizes them, and 2) gives them a social infrastructure to support extremist behavior. This is why YouTube blocks ISIS recruitment videos.
It's a contradiction to believe that both "freedom of speech matters" and "regular consumption of extremist speech has no impact".
No amount of 4chan posts will cause a healthy person to become a violent extremist. And no amount of censorship can stop the rise of extremism. It can at best impact the precise expression of it. It won’t stop people from committing acts of violence or believing insane ideologies, it will just change the content of their manifesto. At worst it can accelerate their rise, as extremists become further convinced society is unjustly persecuting them.