All kinds of things could factor into the different risks based on race/ethnicity. Systemic racism is one, but is fairly unlikely in this case.
But they’re finding out that blood type is correlating with different risk levels, and if true, it’s also possible that blood type percentages vary between racial demographics.
There could also be slight variables in other genetic factors that alter someone‘s risks because of their race. Sickle cell anemia and sickle cell trait are more common in black populations...because we evolved in close association with certain diseases that (peversely) the trait actually helps combat. So, while the DISEASE is a death sentence, the trait is (in some places) a biological advantage for survival.
Soooo much we still don’t know about this monster.
Personally, I don’t begrudge ANY parent for minimizing their kids’ risks of getting this MF bug. Hell, just last night, I was reading about teacher protests and early retirements being triggered by some of the government plans to reopen the schools, so that discussion is getting more complex by the day.