Usually, if it matters, you don’t know their ethnic background. If you did you’d just use their name. For example, assuming everyone who’s black is African can be pretty problematic. Assuming everyone who’s black is black isn’t.
Sometimes it matters when referring to a unique problem a certain group is facing due to their background, like “the Chinese American diaspora”, you don’t directly refer to individuals that way.
Well sure, if the problem is due to something specific then you want to refer to that specific thing, not some totally different thing. Obviously. That’s not really what was being discussed.
Usually, if it matters, you don’t know their ethnic background. If you did you’d just use their name. For example, assuming everyone who’s black is African can be pretty problematic. Assuming everyone who’s black is black isn’t.
Sometimes it matters when referring to a unique problem a certain group is facing due to their background, like “the Chinese American diaspora”, you don’t directly refer to individuals that way.
Well sure, if the problem is due to something specific then you want to refer to that specific thing, not some totally different thing. Obviously. That’s not really what was being discussed.