As a human being with the capacity to understand, communicate, and reason about ideas, you are allowed to determine which ideas are acceptable and unacceptable to you. Everyone has the capacity. Ideas are have meaning, they can be analyzed, they can be judged. The fact that different people come to different judgments doesn't mean
no one can judge ideas, that would be absurd. How to reconcile conflicts of ideology, that is important. Understanding why reasonable people acting in good faith can disagree on very basic questions, that is important, too. But I think throwing up one's hands and refusing to be political, refusing to judge any ideas is irrational.
And if somebody else executes their similar ability to reason through and judge ideas, and condemns ideas you think aren't worth condemning, and perhaps even suppresses that speech to the extent of their capacity, and you disagree with them, of course you are perfectly capable of disagreeing with them, resisting them, condemning them in turn, coming into conflict with people whose exercise of power has consequences you disagree with. That's what being a human being is.
> So we deny them the privilege of debate, because we're afraid that if they get into power, they'll deny us the privilege of debate?
Well, yes. Why is that invalid reasoning? If you analyze the content and aims of fascist ideology, what other judgment could you come to? There are people out there who are very outspoken about what they would do to people like you and me if they were in power and we crossed them.