Radical political groups have had their right to free speech protected by U.S. Supreme Court decisions since around the end of WWI.
It's better for society, I think, to treat kook groups like the "Nazis," as the strange folks they are. They should be encouraged to change their views, mocked with some laughter, and confronted in a civilized way. This National Socialist Movement is unlikely to go anywhere because it is really too laughable. Someone donning a swastika armband isn't telling us very much other than that they are very much out of the mainstream and possibly mentally unbalanced. They might just get a perverse kick out of tweaking society's nose; I don't think any of us know. I think you're confusing the Nazis of WWII with these oddballs.
There are dangerous "right-wing" maniacs like Tom Metzger whom I would consider a much more serious threat than these clowns. They seem more into the Nazi 'fetish" than anything else.
Again, libel, sedition, slander, etc.
Are there different Nazis than WWII?
Is it like the Gold Star Mothers and the Gold Star Families for Peace?
I don't think so. They're Nazis, period.