Sure but what degree of influence is actually "radicalising" or a point of concern?

We like to pretend that by banning extreme communities we are saving civilisation from them. But the fact is that extreme groups are already rejected by society. If your ideas are not actually somewhat adjacent to already held beliefs, you can't just force people to accept them.

I think a good example of this was the "fall" of Richard Spencer. All the leftist communities (of which I was semi-active in at the time) credited his decline with the punch he received and apparently assumed that it was the act of punching that resulted in his decline, and used it to justify more violent actions. The reality is that Spencer just had a clique of friends that the left (and Spencer himself) interpreted as wide support and when he was punched the greater public didn't care because they never cared about him.