In essence, it's a defence of the slippery slope. And not the slippery slope fallacy, as the list included in this article already demonstrates that the slippery slope is very real, extending the approach from terms where the connection makes sense (e.g. the master/slave relationship) to terms where the connection is much weaker (e.g. dummy value).
I'll gladly support the changing of a particular term e.g. master/slave if we draw the line at discussing that term alone on it's merits and justify it's change with specific arguments that for this particular case the benefits outweigh the cost - and the cost is not "basically zero", it requires work on many, many people to change many, many things, it's a nontrivial cognitive cost of changing the habitual terminology of literally millions of people. If it's only about this particular case and we don't concede that "word policing" is generally acceptable behavior.
But if the position is explicitly about the general case, as it seems to be in the article; if we lump together the master/slave terminology with dummy value and expect to extend it further (e.g. the RuboCop debacle not so long ago), then I can't consider that acceptable. If it's piecemeal, then we can discuss specific cases, but if it's all-or-nothing, then I'm strongly on the side of free speech and against the policing of what words are permitted.
If there's no clear, defensible line of changing master/slave terminology that ensures that neutral-seeming (to me) terms won't be attacked as well, then I must defend the general concept and assert that no terms should be changed. The big issue at stake here is whether it's appropriate to make demands to change terminology because someone feels offended, as opposed to making requests (where "no" is accepted) and awaiting consensus. So there's some "line in the sand" (which I don't want to see crossed) at the implied moral right to make demands at the choice of words others use for technical terms. Because it's absolutely unacceptable to have people verbally assaulted and 'cancelled' for things that weren't meant in offence, it's absolutely unacceptable to require everyone to self-censor everything that might be misinterpreted. I've seen how it went back some decades ago in USSR, trust me, we don't want that. If ensuring this means that we'll also have to permit racists to say racist things, oh well, too bad; some things are more important than others, and freedom of speech (practical freedom, including social consequences, not the first amendment about government restrictions) is far more important than freedom from being offended. I strongly support a social climate where misinterpretable things are tolerated and people are free to just live their lives without worrying about stepping on social landmines. So if person A uses a misinterpretable term (like most of this list) in a technical discussion and person B loudly protests its use and calls for social ostracism, I'd want person A to be safe and person B to be ostracized for making unreasonable demands.
And to put it clearly, if someone demands the rest of the world to change from "dummy value" to "placeholder value", then that is an unreasonable demand. If you want to speak differently, you're free to do so, but requiring a whole field to change without a very strong reason is unreasonable chutzpah that should not even warrant attention - and it's sad that here it is, requesting attention.
We have the opportunity to make tech marginally more hospitable to Black developers at basically zero cost to everyone else. Let’s not mess it up!