Ernst Zundel propagandized for our terrorist enemies. Many neo-Nazi writers do the same and have their unholy alliance with Islamo-fascists.
Thats fine. Nail him for that and leave him alone for his holocaust denial delusions.
Right now with the direction things are headed, propagandizing for the enemy will be protected speech, while criticizing the enemy will be punished as hate speech. This is a step in that direction.