I think you've misunderstood.
"Not black" and "White" are different not because of things like the one-drop rule and its legacy, but because there are races other than "White" and "Black" present in the US.
"Not black" includes Native Americans/Alaskan Natives, Asians/Pacific Islanders, etc., not just Whites.
> Our distinctions are related to old Jim Crow notions that 1/64th Black made you Not White. Why not the other way around? If 1/64th White made you Not Black, then the USA would be about 99% white.
Er, no. Because even if modern Black vs. White racial identification were entirely driven by the one-drop rule (its not), there's only about 87% of the population that identifies as either White or Black, so shifting some portion of the Black to White isn't going to make 99% of the population White. Again, there are other races in the US besides White and Black.