I'm fine with censoring holocaust denial content, but I dislike this "Paradox of Tolerance" reasoning. It's too easy for someone to convince themselves that another group is "intolerant" and therefore give themselves moral license to deplatform, harass, or even assault their "intolerant" target. This isn't just a theoretical concern; in practice this is virtually the
only context in which I've seen the Paradox applied. Views that are pretty commonplace and understandable are flimsily branded "intolerant" by authoritarians as an excuse to commit their own intolerance. I could get on board with this Paradox of Tolerance reasoning if we had any sort of reasonable if not objective standard for what constitutes 'intolerance', but it seems like >90% of the time it's "someone who disagrees with me".
Not only is it too easily abused, but by resorting too quickly to censorship the compelling, valid arguments against abhorrent points of view are suppressed. If someone is wondering why racial profiling is bad, we should talk about how American society aspires to treat people as individuals and not fungible tokens of their race--any given individual doesn't deserve heightened scrutiny simply because people with similar skin tone are more likely to commit crimes. By not addressing these questions rationally first, a lot of people miss the opportunity to be persuaded--especially when we are outright hateful toward people who ask these kinds of questions--we risk sending them into the welcoming arms of people with unsavory, pseudo-scientific explanations that vindicate profiling (censoring isn't going to stop these people from finding each other). Of course, not everyone is going to be persuaded by rational explanations, but most will be and we shouldn't deprive society of the opportunity to have fewer racists.
Lastly, this quick-to-censor precedent is only good for as long as the "right" people are in charge of determining who is intolerant, and already the people who are the quickest to cite the Paradox of Tolerance are often the people who espouse racist points of view--ideas that society should be segregated (each race should stay in its own lane, no cultural mixing ["appropriation"], no interracial marriage, no-$race-allowed spaces, etc), that some entire races are guilty of crimes against other races, that race tells us all we need to know about a person ("ugh, the teacher is a $race man. What am I going to learn from another $race male?"), etc.
So yeah, I don't have any sympathy for holocaust deniers, but I worry we're gifting these kinds of unsavory groups a weapon to be used against us in these Paradox of Tolerance precedents.