The inside-the-law approach that works to some limited extent is public community rejection. Things like large groups showing up and standing with their back to the Nazis.
The method that has historically stopped Nazis like this involves getting some level of police cooperation and beating them up
Actually, Ulysses S Grant clamped down very brutally on groups like the KKK during the Reconstruction Era, essentially continuing the civil war against the south in a sense. He ended up reducing their strength significantly and driving them underground.
Unfortunately, an idea cannot be destroyed with military might, it can only be fought by teaching critical thinking skills and sound information gathering and decision-making methods, so people don’t think so stupidly.
https://en.m.wikipedia.org/wiki/Enforcement_Act_of_1870
Note the line that says the law allows the use of the army to enforce it, that’s what Grant ended up doing.
