I wish he would just give examples or at least speak slightly more plainly about his complaint. I would understand his complaint more (and be able to decide whether I agree with him, although I’m fairly sure I don’t) if he would just say something very plainly like “I liked it better in 1985 when you could say X and have zero risk of losing your job.”
There's a quotation that "Great minds discuss ideas. Average minds discuss events. Small minds discuss people." I think the problem is that PG is determined to demonstrate that he has a great mind, and must therefore discuss only abstract ideas. Lowering the discourse to include events or people is not an option. Unfortunately, the essay isn't exactly about heresy, it's about accusations of heresy, who makes them, and if the incidence is rising. So the essay can't really get to its subject.
Lowering the discourse to include events or people would probably disgust people. Most of the heresies people get canceled for seem to range from pedestrian to absolutely vile.
I'm a freedom of speech absolutist, but my only sympathies towards anybody who has been canceled have either been because the people canceling them were extremely stupid, had the facts completely jumbled, and petulantly refused to be corrected; or because somebody sheltered had accidentally shared some inherited bigoted opinion that they had never really thought about in a small, relaxed context, and had that mistake blown up by cluster two clout-chasers trying to break into the opinion-haver industry.
Which wrongthink is not the issue being discussed here and is beside the point. This is about principle. The issue is not being able to hold any wrongthink beliefs (and discuss them) while also holding a job. If you can't think of anything which may be true but also offensive enough to get someone fired for proclaiming it, you may be guilty of being a 'conventional thinker'.
Unfortunately any argument of that form can be rejected immediately on epistemological grounds. Take for instance the argument “we can’t say certain words any more because speaking them will summon an ogre who will immediately kill and eat the speaker…and I can’t give any evidence of this occurring, or give an example of any of these words for obvious reasons.”
There's something to be said for priors here. I personally know three (yeah, I hang out w/a fun crowd) people who have lost their jobs over social media heresy. I don't know (and have never heard of) anyone getting eaten by an ogre.
So yes, I am inclined to believe that modern heresy is a phenomenon, and I am not inclined to believe in ogres.