Dangerous ideas will always exist. Consider that the suppression of opposition played a large role in the Nazi takeover, and was likely as critical (if not more so) as the ideology itself. Dangerous regimes control the flow of ideas.

Circumstances will always make some ideas particularly vile; however, protecting ideas when it is difficult reveals the true nature of our system. We will always desire to make exceptions, and the motivations to so will often be genuine and well-founded. But the exceptions that we would seek will change over time. Instead of weakening the protections for ideas, we should rely upon those protections to reveal dangerous ignorance for what it is.

They have every right to do and say as they please, as long as what they do and say are not an attempt to limit the rights of others, which is precisely what nazis do.

Doing and saying are very different things. For example, I fully support someone's right to campaign for the prohibition of abortion, and to draft, and vote for legislation that prohibits abortion. However, as long as abortion is legal, I do not support someone physically restricting another from having an abortion, or harming them for doing so.

We do not care enough about black people in this country, and our law enforcement reflects it. IMHO this state of affairs is more a result of our ideas (ones prevalent in the general populous) than it is due to those of neonazis. Thus, IMO suppressing the ideas of neonazis would be a dangerous window dressing.