It was due to this:

A student asked me: “Do you think one of my classmates should have been suspended for using the N-word in a video from two years ago?”

I said: “Well, wait — what exactly happened on this video? Did she actually call someone “nigger”? Or was she just using it in passing, like quoting the title of a book?”

Because when he asked for context around how the person said “nigger”, he didn’t self-censor when making reference to the word.

That’s it.

That’s how bad this juvenile cancel culture mob has become. They let some 15 year old activist wannabe complain to the paper and get him fired.

It not only ended the man's career, it tarnished his legacy. He worked 50 years, and this is what he'll be remembered for. It's really screwed up. The Times really mishandled this one. I hope those involved one day come to regret what they've done. Sometimes... Regret is the best form of karma we can get.

This article comes across as very "inside baseball" i.e. the crowd who are intimately familiar with the ongoing melodrama in journalism, the history of the NY Times, etc. See his reference to his "until now anonymous comments in an internal Times report", for example

Aye, same.

The gist is that he doesn't vibe with... someone?... and finds that his colleagues have wildly different expectations about... something?