As quick clarification, if you aren't aware the Nationalist Socialist (AKA, Nazi) Party of America genuinely is a party that is protected by the First Amendment[1]. Conversely attempting to suppress Nazism forcibly didn't work either. Remember, Hitler and other early members of the Nazi party were imprisoned. It didn't stop them.
And regardless this is straying from the core point. Of course, advocating the mass extermination of Jews, Roma, or any other group would be grounds for a company to fire employees that make those statements - I did not and do not attempt to state that every piece of speech protected by the 1st Amendment should be allowed in the workplace. Rather, the simple principle is that tolerating a view that some people consider intolerant is not, itself, an act of intolerance. Let me put this in a scenario that is more appropriate to a workplace:
* You have two co-workers, A and B.
* A thinks that affirmative action (structuring hiring policies such that non white & Asians, and women have greater chance to get offers than non-diverse candidates) is necessary to have a tolerant workplace, and by extension not having these policies is an intolerant situation.
* B thinks that discriminating on the basis of sex or race in the hiring process is intolerant.
* Both A and B go to HR claiming that the other is making intolerant statements.
I would argue that if HR takes action against _either_ employee that would be an act of intolerance. Allowing A to make that statement isn't an act of intolerance against B, nor is B's an act of intolerance against A. Sure, I get that A _believes_ B's viewpoint to be intolerant and vice versa. But the company's decision to allow both statements is not an act of intolerance because of that. This is what I'm getting at by saying "there is no paradox of tolerance" in allowing speech. True, individual speakers may think the other is intolerance. But there is no intolerance in allowing these conflicting views to co-exist.
[1] https://en.wikipedia.org/wiki/National_Socialist_Party_of_Am...