pg employs this style of argumentation so frequently that it's almost time to devise a new term for it; for those sympathetic to his argument, realize that it is not an argument for free speech but rather an argument for free speech without consequences.
pg likes to do this thing where he takes some noble instance of a counterexample (e.g. Newton being declared a heretic for important scientific discoveries) and uses it to butter up the audience to be sympathetic to what ultimately becomes a defense of racism/sexism/whatever-ism you want without consequences because, wait a minute kids, the homophobes and racists might be right! What he manages to do rather surreptitiously, is attempt to get abstract enough that he can bring all forms of discourse to the same level. He reduces all discourse to the "search for truth" but if he had even a passing knowledge of speech act theory, any linguistics, Wittgenstein's later philosophy etc. he'd quickly recognize that much of the speech and discourse human beings are engaged in is not about finding the truth.
Ultimately, we determine our own values, and just because something is true does not mean it aligns with our values. Can a statement be "xist" and true? (let's call it what it is, pg means the negative isms here, racism, sexism, etc. (see how suddenly it's hard to agree with him when he says what he means and doesn't hedge? he hedges and hides behind abstraction because he realizes his position is indefensible to most "conventional minded" (read not bigoted) people)) yes of course. a statement can be totally racist and somehow true. Does that mean we should accept all these statements in all realms of discourse and that such the authors of these statements should be free of consequences because the statement happens to be true. But we don't just live in the world, as humans we have agency and we might decide that when truth and morals conflict, we prefer morals.
Is calling someone ,e.g. racist an attempt to stonewall their speech? Of course it is. People don't like racism. Paul claims this is a "wave of intolerance" while conveniently ignoring the fact that the positive content of "xism" speech is also a vehicle of intolerance, and usually a much more aggressive one at that, to the point that your speech is trying to do the work of not tolerating the very existence of classes of people in society.
Human society is an amalgam of all sorts of discourse. Even we "conventional minded" simpletons can recognize that the intent of a "xism" discourse is usually not truth seeking so much as it is the active exclusion of certain classes of people from equal participation in society. It's nice to think everything is reducible to something like "Newton V. the Church" but this is a reductive move that ignores all the particularities of such discourse and tries to make things that are fundamentally distinct (scientific process v. racism, sexism, all manner of exclusionary discourse) equivalent. Should scientific exploration be punished with the stake? No. Should racism be punished with loss of a career? Possibly. As with every moral problem, we often need to judge case by case. Can "cancellations" be a way too severe given the violation? Of course. Can they also be appropriate? Sure. Moral problems are not reducible to a abstract mathematics that removes human particulars from the equation or to technical description and the part of your brain responsible for empathy must be pretty lacking if you think otherwise. Morality is not some abstract calculus. That's why we have juries and judges.
I'm really sick of pg using his platform to come up with these absolutely piss-poor pieces of sophistry that are ultimately defenses of horrible shit veiled behind "smart" abstract language so that "conventional minded" people are tricked into thinking this guy actually has something interesting to say about society and isn't secretly a massive bigot. Continue being a great capitalist or whatever but keep the pseudo-intellectualism to yourself, please.