That's, perhaps unintentional, misunderstanding and misrepresentation of what people worried about it mean by it. The problem with "cancel culture" is the propensity to "shoot first, ask questions later", the doling out of punishment grossly unproportional to the crime. Like in this case - ruining one's entire career for the crime of being pedantic and tactless on a semi-public mailing list[0]. Or, in another, overhearing a joke in a private conversation between two people and making a social media mess that resulted in termination of the joker.

The problem with "cancel culture" isn't the part where it aims to hold people accountable for their behavior. The problem is with the mechanism, which involves setting off a chain reaction. There's the wronged or felt-offended party and initial outrage, which gets amplified as the stories get reshared and republished, usually accruing misrepresentations and outright lies in the process, until the reaction fizzles out in a day or three, and punishment happens. You'll note here that the final impact is not correlated with the scale of the initial wrongdoing, but with how many people get outraged how fast, and how far they reshare, all of which is moderated by how misleading can the story be made and by what else is currently on the news.

I think it isn't fair to dismiss concerns of people worried that "holding people into account" - not just powerful ones, but regular ones too - increasingly often involves attempts at setting off a social equivalent of an ad-hoc, hastly-made fission bomb.

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[0] - Yes, there's apparently patterns of worse behavior going back many years. But pulling the trigger in the middle of one of the bigger scandals in our industry, that's awfully convenient and points towards the actual reason not being related to past behavior.