> Or would you say that it's unacceptable to use race as a variable at all,
You're arguing against a claim that neither TFA nor anyone here made. TFA doesn't suggest doctors should ignore past research that examined race - it argues that future research should examine specific identifiers instead of made-up ones.
> often neither you or the patient actually know their ancestry
Sure - which is why using race as a proxy for ancestry is a bad idea. If a drug has known risks to people of West African ancestry, and you have a patient with unknown ancestry, then you don't know whether that drug presents risks to the patient. Whereas, if the research on that drug had only reported "risks to black people" without examining ancestry, then you would believe you could tell by looking at a patient whether the drug presented a risk - and you'd be wrong.