I can tolerate a very wide range of political beliefs, but when a group repeatedly crosses the line from belief into hurting or killing lots of innocent people, that's it. They are no longer political but simply evil. I can even understand extreme Islam, but Al Queda, Boko Haram, etc. deserve annihilation because of their acts. Joining an organization with a history of genocide like the KKK should bring a death sentence.
If we [Americans] don't make this a widely understood policy, it just tells the worst of us that it's safe to express their worst sides. Joining the Nazis or KKK should be dangerous to your health and safety.