There's a time dependency in some of this. What "diversity" is, even from a purely left-wing perspective, has changed a lot within my lifetime. I was born in 1978, and when I was growing up, the left-wing diversity perspective focused on "race blindness", MLK's dream about his children being measured by the quality of their character and not the color of their skin, and that sort of thing. Now... well... I know a lot of you on HN are very, very leftist; how does that sound to you now? I'm serious about that question. I'd guess a lot of you, if you were careful and thought about it, would have a hard time answering that question, because it isn't a "right wing" perspective, but it certainly isn't a left-wing perspective any more, which now focuses intensely on looking at people by their identity groups, to a degree that (very, very much no sarcasm here) greatly exceeds anything like the KKK, who merely looked at your race, rather than race, gender, disability status, and all the rest of the intersectional categories. The idea that anyone can be race-blind is seriously heterodox stuff now; grounds to get one instantly accused of not just racism, but subconscious racism.

There's a lot of people still operating under the assumption that the older meanings of the terms are in use, because most people have better things to do than to stay up-to-date on this sort of stuff when they've got lives to lead and their own problems, not to mention the fact that there's some deliberate obfuscation that tends to go on.