In olden days when nationalism was rampant in many parts of Europe, neo-Nazi nationalists would march through streets dressed in black with music blaring and shouting their epithets of hate. A group of Swedish nationalists wanted to march to honor a dead king, but their attempt was met with angry insults and rocks thrown at them by liberals who wanted to deny their enemies an opportunity to display their ignorance. The Nationalists were guarded by police and allowed to do their thing, shout their anger, and then swiftly depart on trains.
The right to demonstrate is inherent in any democratic society. Those who hate neo-Nazis and resort to armed violence are acting just like the group they dislike. Let them march, let them shout hate in the open. The vast majority of people will shake their heads at the ignorance of these people who belong in a different time and a different place. If progressives use violence against those who preach violence, they have met the enemy and they have beome the enemy.