There is the defense of free speech but history tells us to be wary of when speech crosses the line into action.
The problem is that in America, there has been a history of white supremacists also being terrorists. The Klan would most likely be regarded as a white supremacists group yet historically their members were known for committing crimes like cross-burnings on the lawns of Black families in the South, as well as lynchings and kidnappings.
Sure, now they are known for marching and meetings in conference suites in federal buildings but White supremacists also have a history of transgressing beyond hateful speech.
For someone like me, who would most likely be in their cross-hairs, it becomes muddled and more complex than a simple question of whether they have the right to exist as an entity.
I wish I could say I'm surprised by the mistrial in the Michael Slager case, but I'm not. Even with a video as chilling as the one in this case some people won't convict. I guess the bright side is that he'll be retried.