You always know who you are dealing with and what they represent when they are open enough to want to fly a Nazi flag at their protest. And even to the ones who didn’t hold the flag or support it … how many people were actually around to prevent or stop it from happening in the first place.
It would be less provocative to say “don’t hesitate to put hands and feet wherever they need to go to destroy naziism”. Also much less succinct I suppose.