What do you think is important here? Shunning people whose opinions you abhour or aquiring true beliefs.
I thought sticking to the original topic would be important, and I don't shun people whose opinions I abhor. I live in the South, and that would be a lonely life. With relevance in mind, we move onto
People tend to mean different things by "racism". I what to know what you mean by it.
I'm not a university administrator or faculty member or newspaper editor. We're talking about those people. On this topic, those people are the ones responsible for recognizing false and nasty beliefs, e.g. racism. It's important to know how they evaluate it. And they will evaluate it, even if you want them to pretend that they aren't doing it. They'll notice what David Irving has done even if you very politely ask them to not do so. (I'll put this out there: I would hire Irving, assuming he was only to teach advanced students, were it not for his history of suing critics.)
As for what I mean by "racism", I suppose I wasn't clear before, so here it is: you're not Socrates, and I am not your pet monkey.
Addendum: If you want people to answer your questions, I suggest answering theirs.
On this topic, those people are the ones responsible for recognizing false and nasty beliefs, e.g. racism.
So you won't say what you mean by "racism" but insist that it's false and nasty. I've heard different definitions of "racism", a number of those definitions wind up including making certain statements that are in fact true, or at least likely to be true.
If you want people to answer your questions, I suggest answering theirs.
Which question in particular were you refering to?
Related: Heuristics for Evaluating the Soundness of the Academic Mainstream, Admitting to Bias, The Ideological Turing Test