Radicals aren't the same as extremists. And that is an important distinction to understand when dealing with politics. Being armed and willing to defend yourself isn't an act of extremism. Being violent towards violent fascists isn't extremism. It's community defense. When you break down politics into it's most base element, it's about the distribution of the legitimate use of violence. Understanding and working within that framework isn't extremism, it's politics 101. Philosophy Tube has a good video on this in relation to fascism. Skip to ~20 mins in for the violence bit.