It has some relation to ethnicity which is a real if difficult to pin down thing.
Not helped by the fact that attempts to pin it down open one up to accusations of being racist.
It's yet another of those things that drives me mad about the dominance of the American narrative. I'm supposed to not notice that there are slight differences amongst features that give clues to the general geographic location one's recent ancestors lived in, because white Americans think that's racist.
Those same white Americans are the ones who tell us off for cultural imperialism etc when we care about the injustices faced by our sisters of colour in other cultures, and accuse us of trying to impose our colonial narratives on other cultures.
There's some very hypocritical projection going on there, and I fail to see why I should be expected to champion the rights of my English-speaking black sisters while turning a blind eye to the systemic denial of women's rights when the recipients don't speak my language.
Sorry, I may be ranting slightly.
The phrase "educate yourself" comes up again and again.
Mm. I'd quite like to do this. But when it comes to book recommendations I'd like to know a bit more about any given author than simply their skin colour. Because I'm going in blind here, and it strikes me as a bloody stupid (and racist) idea to assume all black political writers hang around the same point of the political spectrum, and I don't want to fall into the trap of thinking "this author's black so their interpretation is the obviously correct one".