Interesting, my grandmother who was extremely high waisted always said she swam just like a rock. The rest of the family is all “normal” and all swim like fishes. Don’t know if that had anything to do with anything but an interesting piece of info.
I really don’t know why blacks aren’t generally attracted to swimming but it surely can’t be that minor of a physical difference, that would only affect super athletes at the highest levels of competition, white people run and race in their youth, although they probably won’t be entering the Olympics.