My sense is that there actually is no real reason in many cases for these changes to what is supposed to be ok or preferred or not ok.
Very often it seems like the explanation is made up to justify making a change. It's nothing that a normal, rational person would even differentiate. Or if they saw a difference of emphasis, one version still isn't less offensive - because neither are offensive.
Quite a lot of the terms here that they are saying are now not preferred - BAME, BIPOC, etc, came about in exactly the same way - some academic just decided that this was the new thing and someone felt they had some kind of authority to tell the rest of the world that is what they should say.
This is not a new thing - even back in the 60s, some of the racial words that fell out of favour weren't rejected because the community as a whole didn't like them, it was a small group, or even one person in some cases who felt empowered to decide that word wasn't the best one to use any more, even though many members of the community being described continued to use that language for decades afterwards.
The pace of it has exploded though where words that came into use even a year ago as the new "correct" thing start to be questioned, and words of two years ago are now offensive. Some words (Lainx comes to mind) don't seem to have any kind of use in the relevant community at all, they are confined to academia, the white professional middle classes, and a few people who make a living as activists.
I think its worth asking who drives this stuff, and why? There is something really concerning about it IMO.