I’m using race and ethnicity interchangeably, as I don’t think the difference matters to the point I’m making. Ditto with my use of “black” and “white”. I would have thought that a wee bit of charity and common sense would get what I mean, without crucifying me over semantics. Although this would be the perfect thread for that to happen!
But yeah, a restricted genetic pool is the most important factor for biological differences between “races”. Ashkenazi jews have some really interesting genetic quirks, likewise Irish travellers (who have extremely rare metabolic disorders) mainly down to an extremely restricted gene pool.
On a larger scale, the differences are more subtle but they’re still important. At the end of the day it’s preposterous to try and claim that races/ethnicities that have phenotypical differences that are blatantly obvious to the naked eye don’t have important differences “under the hood” as as well. Almost as preposterous as the idea that these differences don’t exist at all.
I get your first paragraph, it makes things easier but these terms have no reality. I won't crucify you on that because we all do it, I think that I know a bit about the subject and still lazily go with the easiest terms. Now if we are talking about science and medical implications then we really shouldn't mix them and we should ditch the term race because it has no meaning, no reality. Identifying ancestries and genetic pools is on the other hand important but race and ethnicities are social constructs.