Tech has a very clear problem with continued sexism and racism. That's why the terminology we use matters. There's no equivalent dynamic around the history of the word "kill."
How's it absurd? It's the same logic. He's offended but the difference is he's not claiming a specific race. Kill, master-slave etc. in a technical context aren't associated with race, yet now that someone's claiming the word "kill" is offensive you have a double standard and are dismissive, like you were in replies to me, that their logical assertion is absurd.
Maybe it's relevant to point out that white Americans perpetrating slavery against Africans is by far not the only instance of slavery in world history. So in the light of this, it's a little silly to be terribly afraid of the terms "master" and "slave" due to presumed racial bias.
For example, Mediterranean people were for a long time regularly kidnapped by Arab raiders from the south. Vikings kidnapped people from the British isles. Etc.