People who are supposedly leftists who believe in essentialist racial categories worry me. Race is a social construct, doesn’t mean that it doesn’t effect shit in hideous, evil ways, and the fact that the lines are drawn in arbitrary as fuck ways shouldn’t draw attention away from the fact that the construct of whiteness has caused the loss of countless lives not to mention languages, cultures and histories.
Like human genetic variation is a gradient not a thing with clear lines that match national or even continental borders. Borders on maps are socially constructed but that doesn’t mean they don’t affect real people’s real lives in terrifying ways. Who has been socially constructed as white has varied by time and place (and no this doesn’t mean that racism against white people exists because racism has always been carried out by people who were in that time and place white, against people who were in that time and place not white).
Which ethnic/cultural groups are considered white is indeed socially determined but that doesn’t mean that the oppression isn’t real
Similarly what forms of sexuality are considered normative or straight varies by time and place (in much of the Ancient Greek world, for example, a straight guy could have plenty of homosexual sex provided he was on top and remain within their category of sexual normalcy).