Nazism didn't go through some kind of Martin Luther style academic and cultural reformation in the last 80 years. Neo-Nazis are the same as the original Nazis. They have the same ideology & the same ambitions. They're literally incompatible with Western liberalism & enlightenment.
Neo-Nazis are just late-stage Third Reich acolytes, sympathizers, and insurrectionists. They're still trying to fight a war that they lost to terms of unconditional surrender. It's frankly shocking that they're given the deference of being just yet another political voice in the diverse landscape of voices. They are not. Very, very few modern political movements were defeated explicitly at the tip of a spear instead of the stroke of a pen. Nazism is in scarce company in that regard.
There's no point at all to engage any of it as though Nazism is the same as normal political speech. Allowing for ideological recidivism and re-litigating WWII sort of defeats the purpose of having fought that war and conquered them to begin with.
It would make way, way more sense to consider them enemies of the state and deal with them as such.
Western society, including the Supreme Court, has decided free speech ends where harm to others begins.