Horowittz's (I think, reasonable) point was that Bond (as written by Fleming) was an upper-class Empire colonial. Elba, thought Horowitz, was not right for Bond as Fleming invented him. However, the phrase generated accusations of racism. Horowitz apologized to Elba and Elba was gracious rather than rude in accepting it.
Subsequently, Horowitz wanted to feature a black protagonist in a new novel. An editor in the US warned him off doing this, effectively saying that white people could not create black characters (we are here entering the world of cultural appropriation, and the feeling by people that those not in their own social history are incapable of writing "genuine" characters). As Horowitz observed, that presumably means all of his characters in future have to be 62-year old white Jews. The nature of fiction-writing itself has been annihilated by a US editor.
From my own point of view,the problem is slightly different. But I am not alone.
As people age, their linguistic "free recall" deteriorates. You forget names, you can't get the right word, even though you know you know it. What also happens is that names you learnt later in life disappear faster than names you learnt early in life. And words you learnt later in life also disappear -- get harder to remember.
A few months ago I found myself unable to remember the words "Down's Syndrome". I could remember the world "mongol", because that was the word used to describe someone with Down's Syndrome when I was a child. I first heard the term "Down's Syndrome" when I was about 16, because I remember having to ask what it was.
Anyhoo, I was now in the situation of trying to describe an actor in a TV series without being able to remember the "right" terminology. This was solely because the synapses in the brain, the connections, age just like the rest of your body. Free recall gets weaker. But the synapses, the connections formed when you were aged 0 to 16, they last longer.
Another time, I found myself thinking of the concept of "mixed race" and, once again, the phrase that came first to mind was "half-caste". because, once again, this was the phrase used in my youth. I can't remember when I first heard the term "mixed race", but I was probably at University, mixing with the middle classes *en masse* for the first time.
The "polite" term for people of colour was "coloured" "Negro" was okay and the "n' word was rude. There was the National Association of Coloured Peoples and Martin Luther King referred to "the Negro". "Black' as the de rigeur word came in in the late 1960s.
The word "spastic" was the norm (remember it was called "the Spastics Society" at the time. I did now know the words "cerebral palsy" or "spina bifida"). But the terms "spaz" and "mong" were insults. They were rude.
As recently as a decade ago the term, "third world" could be used without insult. Then it became "North" and "South". Today it's called (somewhat inaccurately) "emerging markets".
Other terms that did not exist before I was 18 include "African American", "Native American" (we just said "Red Indian").
Now, my point here is, I might find myself unable to recall the "correct" word or phrase, but I would still know that a new phrase had supplanted it. But someone in their 80s might refer to "coloureds" not because he or she is a racist (although of course they might be!) but because that is the word they used when they were younger. Learning new words gets harder and harder.
So what if that starts happening to me? I start using "unacceptable" words because those are the ones hard-wired into my aging brain. It's not my attitudes that are locked in the past, it's my linguistic capacity.
Youth seems unable to comprehend this, and, by god, if you should happen to use an old-fashioned word, you soon know it from that smug purse-lip smile that they deploy -- meaning "without saying "look how enlightened I am compared to that old fool".
So, far easier to avoid mixing with such people, so that you don't risk the silent mockery.