[DavidSharff]

Yep, I had struggled down these lines too but the always lucid John McWhorter cleared things up for me, and as a linguist it's right up his alley.

"On metaphor, master is a useful example. The basic concept of the master as a leader or person of authority has extended into a great many metaphorical usages. One of them was its use as a title on plantations worked by slaves...That makes sensible the elimination of certain other uses of the word, which parallel and summon the slavery one...in the 1970s, such schools had just begun a call to stop having male teachers called "master" and female teachers called "teacher," in favor of having all instructors called simply "teacher"...This meant that young subordinates had been calling white men in positions of authority "master," after all—including, by the 1970s, more than a few black students. And today's call to stop referring to technology parts as "master" versus "slave" attachments follows in the same vein, as it directly channels what was so offensive about the slavery usage...However, other extensions of the word master do not meaningfully resemble the plantation one, and only a kind of obsession could explain spraying for them now. Are we to consider it racist to refer simply to mastering a skill? To master tape as opposed to dupes...The plantation meaning of master was one tributary of a delta of extensions of the word; it should go, but we need not fill in the entire delta."

And for emphasis I'm pulling this one out of the main block:

** "To be human is to make distinctions." **

https://reason.com/2020/08/12/is-your-master-bedroom-racist/