How to deal with these despicable cranks if I encounter them in person, handing out leaflets on the street?
- Don't stoop to their level - if anger rises, stuff fists in pockets.
- Don't give them the satisfaction of listening to their conspiracies - walk on.
- Above all else, strive to be better than them - their "heroes" committed an atrocity in self-righteous anger, so avoid acting in self-righteous anger as much as humanly possible.
It's not easy, but it's something to aim for.