I think this is because our historically racially polarized nation, for all its genuinely forward progress, is still hugely uncomfortable with (and disapproving of) the deeply intimate form of integration that it takes to produce a bi-racial child. There are a lot of people of all races who are not racist in a hateful or discriminatory way, but who are nonetheless opposed to mixed race procreation. I believe this view is often more about the longstanding desire to preserve one’s culture than it is some fascistic devotion to racial purity. In the main, for example, Jews believe in the importance of maintaining Judaism by rejecting the cultural dilution of religious inter-marriage.
It’s also important to remember that America’s history of our own brand of actual fascistic devotion to racial purity evolved from the economic demands of Slavery. Even though countless enslaved Africans were regularly making their tortuous way through the Middle Passage, it was essential that the slave stock be replenished without incurring the costs of new purchases, which is how the One-Drop Rule came about. “All it takes is one little drop of Niggra blood and you’re a, Niggra, too,” wails Elizabeth Taylor in Raintree County as a Civil War-era southern belle who’s losing her mind, because she fears her Mammy is really her Mommy.
And so it goes. Slave owners automatically owned their slaves’ children. And since a considerable number of them were the products of unions between white men and slave women, the One-Drop Rule ensured that the herd would be increased, even if the kid looked white (like me) or very light (like Obama). Out of this was born the ranking of house slaves and field slaves, the former being light skinned (considered more attractive, civilized), the latter dark (those ugly beasts...); and from that came the self-hating hierarchy among slaves themselves that embraced the standard.
These distinctions are not unique to American racism; Apartheid South Africa expressed its version through the categories of blacks, whites, and coloreds, a laundry-based separation that regarded those of mixed race as a separate class, still inferior to whites but to a lesser degree than blacks. Indeed, it is their institutionally racist form of racial distinction that has contributed to our country’s rejection of bi-racial as a legitimate, personal, third category of racial identity, one that has the capacity to enormously enhance one’s ability to be a “uniter,” a transformational figure.
Bi-racial people have always been viewed as race traitors by both races, light enough to often have an easier racial time of it, even sometimes be able to “pass,” and just not-white-enough to be subject to the same laws and most of the same discriminations. Getting past all this confusing shit to a point of understanding, self-acceptance, and a sense of broadly racially inclusive self-identification, is a brain trainer all by itself. If it doesn’t make you crazy, it can make you exceptional.