Activists have identified various expressions as racist, sexist, homophobic, transphobic, or otherwise bigoted and argue that treating those expressions as beyond the pale — like we treat overt racial slurs and Holocaust denial — would improve society by making historically marginalized people closer to equal.

Exactly. That's what totalitarians do. There is a CONSENSUS about where "the pale" ends, but SJWs act as if it ends wherever they can get a Twitter mob to say it ends. At some point the Overton window gets so small it might as well not exist. How can anyone not hear the oxymoronic silliness of calling a “microaggression” “beyond the pale”? My free speech is useless in this regard: words fail me.

One could disagree with this line of argument, of course, but it’s been pretty successful, influencing various institutions and persuading many young people.

Yeah, it’s a bad idea whose time has come. How is that an argument in its favor? Do I really have to list “pretty successful” arguments that didn’t work out well?

Charges of hypocrisy are inherently ad hominem and therefore fallacious. It makes no difference whether Bari Weiss is or is not a hypocrite. The Harper's Letter was not an appeal to the authority of its signers. It was an appeal to the intelligence of its readers. Which is not to say that Mr. Grossman's attacks on Bari Weiss have any weight. There is no effort at cancellation in the tweets he links. Maybe that's why he coyly says that she "goes after" people, vaguely implying cancellation in the context of this article, but not actually alleging it.

I only wish our awful President had not ruined the word “sad” for the rest of us, because I can’t think of a better one for so lame a defenses of such smug nonsense.