But that'll be fixable soon enough, so who cares? Also, does that statistic apply to new mutations or recessive genes?
To my knowledge the Denisovans, Neanderthals, and Homo sapiens are/were all subspecies of human. I wouldn't compare that to modern ethnicities or whatever, because that isn't a good can of worms to open and reeks of white mans burden and imperialism.
Subspecies, so they'd be Homo sapiens denisova probably.
They were doing it to keep out genetic defects. Their version of a defect included being black, but still to remove defects. They were slightly insane—shocking I know—so they might've considered encouraging inbreeding at some point, although considering the "freedom" they gave their scientists, that would have been short lived. Now I may believe in heavy welfare, high taxes, and in cameras recording everything—I wouldn't call it surveillance, because it's complicated—but I am still a liberal damn it, so let people do whatever they want; we can fix it later.