Race has no biological basis. It is a complete social construct.
Race is a social construct. Just like you folks say white people or black people. Ethnicity and genetics are not social constructs. They have a basis in human history.
Just like people say Asian or Indian. So many people say Indian as if everyone looks like Apu from the Simpsons or Kumar from the White Castle movies. And yet you don't see that it's one of the only countries in the world, where 4 socio-genetic groups have resided for over centuries. Mongoloid, Caucasoid, Australoid and Negrito. Go to North India, you'll see light skinned Indians with green eyes, go to the East, you'll see Indians with asian features, go South and you'll see Indians with aboriginal and samoan features etc.
So you can just say hey, we're all equal. We're all humans yes, but we have enough genetic diversity and differences. It's not about homogenization into one 'race' but about respecting all races and never demeaning someone because of it.
As for the debate on dark skinned, light skinned. There has been so much interracial marrying in the US, large portions of North Africa have seen massive migration from Arab countries etc. Go to Libya, Ethiopia, Algeria, Morroco, Tunisia etc. You'll see a large group of lighter skinned Africans. You can't just say oh she's black, or he's not black.
As for this discussion, we haven't had adequate representation of non white males, let alone having black female protagonists. Despite being the second largest minority group in America, Hispanics are still underrepresented in all facets of American society, from media, politics, sports etc. Have we even had a single 'East Indian' protagonist yet?