If you're thinking that his musings are going to be an uncreative recycling of greatest-hits complaints about out-of-control student lefties utterly unmoored from any actual account of contemporary campus life, well, you'd be mostly right.
We do get obligatory swipes at "microaggressions", and fury at accused sexual assailants being adjudicated under the exact same standard of proof they'd encounter were they sued in court (and a far more protective standard than they'd be entitled to in the workplace -- which is to say, there is one), and no less than three references to "cultural Marxism," which is always a good signal to turn one's ears off (on a New York Times editor's ambitions to be "intersectional", he writes aghast: "Does she understand that the very word intersectional is a function of neo-Marxist critical race theory?" Does he understand how many Marxists -- "neo-" or otherwise -- would choke to hear that?).
Thankfully, Sullivan spares us a literal appeal to the First Amendment, but his invocations of its "spirit" appear to collapse "censorship" into "outgroups publicly disliking what I have to say", and delegitimizing their temerity is more or less the core thesis of the argument. Free exchange of ideas indeed.
But I confess that Sullivan did introduce me to one element of PC-culture that was genuinely new to me. These were the "sensitivity readers", by whom Sullivan tells us "Books are censored in advance ... to conform with 'social justice' protocols."
Goodness, that sounds positively awful! But fortunately, Sullivan provided a link to educate us on the contours of this new threat. And there, we encountered a truly harrowing tale: a young-adult author who ... voluntarily reached out to a readers from a community she was writing about to elicit their reactions on her draft.* Yes, we've finally reached the stage where even speaking to outgroups is a form of "censorship". How indeed could the free exchange of ideas survive such terrors like ... talking to the sort of people you're writing about? (To be fair to Sullivan, there's an element of self-interest in play here: one highly doubts any of his ideas could survive the encounter).
There's something to be said about cultivating a spirit of open inquiry that goes beyond opposing de jure censorship. It should be obvious that "speaking with people different from yourself and modifying your views in the wake of the encounter" has very little to do with that spirit. But the larger problem writers like Sullivan obstinately fail to grasp is that part of open inquiry includes considering whether our positions or ideologies create or perpetuate injustices (whether against socially-identifiable outgroups or anyone else). If censorship can exist beyond the formal power of the state and includes leveraging social power to preemptively prevent certain views from being heard, than there's almost certainly no more committed censor in Sullivan's column than Sullivan himself.
* Admittedly, the article indicates that sometimes "sensitivity readers" are not hired directly by authors but rather provided by the publishing house. I can sympathize with how this may feel like "censorship" to a writer, but in our more sober moments we tend to call it by the more prosaic name of "editing".