Nazism should not be protected under the banner of free speech.
It is not a difference of opinion. It is not an opposing political ideology. It is a call to eliminate certain groups from existence. Last time I checked, it's illegal to call for people to murder Jews, Black people, LGBTQ individuals, people with disabilities, and anyone else whom Nazis would like to have murdered. This is as much "free speech" as giving orders shoot somebody.
A Nazi is always at war. There can be no peace with an individual who actively tries to wipe people from this Earth for what they were born. There isn't any "hearing their side of it."