>>211838071
Same as everything else.
Something happened to people or the ways in which people are told what they are supposed to like.

>How and when did this happen?
To be serious for a moment, TOS is not TAS is not MovieTrek is not TNG is not DS9 is not Voyager is not Enterprise is not anything else since.
It shifted, so the fandom did too. It's largely in line with industry trends.
See also >>211839949
>"the new stuff is making Roddenberry turn in his grave"
Roddenberry had a native american fetish which was perverted in TNG to have actual native american looking actors (and an asian one for some reason) with a "muh land" politics plot. This had nothing to do with having sex with white women wearing fake injun dresses in teepees. As far as I recall native americans no longer exist in any Star Trek. He'd be really upset by this, and this is just one facet, there are hundreds of other things that were slowly changed, removed entirely, or both.

>>211842476
There is fandom overlap but LD has more appeal for angry black womyn whilst R&M has more appeal for angry manchildren.