I hear what you're saying but go on any social media today and you'll find hundreds, likely thousands of people claiming people are sexist, racist, ageist etc. because of the most innocuous comments.
These are full-grown adults doing this. Many of them have prestigious jobs in media, universities etc.
Really not hard to imagine a scenario where teenagers are looking for scalps to show how "woke" they are. The author fully admits that he comes off as an asshole sometimes. Maybe he was a bit of a jerk to the kids and pissed them off so they decided tattling on the guy for "being racist" would be payback.
I saw shit like this happen in high school all the time and it was well over a decade ago.
My partner is a teacher and I don't know how many times her students do shit like complain to the principal or guidance counselors that she's being unfair to them. Marking them absent from class for no reason when they attended via zoom and when it's investigated it turns out the kid had the camera off and didn't respond after being called on repeatedly.
Is this actually what happened? I don't know, we only have this guy's side of the story. Literally no one in the NYT or elsewhere has any evidence first hand or otherwise that he said anything worse than what IMO worst case scenario might be described as ill-advised and potentially insensitive.