Edit: this question has been answered now. Thank you to everyone who took the time to help me understand.
the premise that race is not a natural, biologically grounded feature of physically distinct subgroups of human beings but a socially constructed (culturally invented) category that is used to oppress and exploit people of colour.
Okay… But we can take a DNA test and get our ancestry, telling us what percentage of what races make up our overall ethnicity. So how is race a social construct and not a biological feature, when we have a scientific method to determine our race? This part of the philosophy has been bothering me ever since I read it, and I’ve been hesitant to ask because of how offensive people get when you question this system.
Just nitpicking, but there is a biological definition of race (albeit informal), which you quote the definition of. it’s just that it cant be applied to humans because (as your quote mentions) there tends to be greater variation from within human “races” than there is between some “races”.
There’s also the issue that there’s no “boundary” or distinction between the human “races”, and an actual race would need to be distinct from the rest of the specie population in order to be recognized as an actual race.