If they wanted to create a generic term that wouldn't have attachment to color of any kind, they could have. The term black in and of itself is no different than octoroon or quadroon - which could've been used to. Many biracial children don't feel the term "black" fosters unity either.

Why black? Because at the heart of what all this is about is the darkest skinned black person NOT the lightest. Had our culture been exactly like those of various whites, that distinction still remains.

Everyone else is included because we had no choice otherwise, the one drop rule is a white creation, not a "black" one. Across the diaspora, you take Mariah Carey around & nobody is going to recognize her as a black person, its preposterous. In various other societies (who've had similar slave/oppression experience) there is a "mulatto" caste, ie South Africa. The fact is even in America, the darkest skinned among us are the majority of our numbers. There wouldn't have been a "black" movement if we all could've passed. And whatever movement we developed wouldn't been called a "black" one if we all could've passed. At the heart of the term is reference to complexion.

And Malcolm X (red) married Betty (ebony) in part because he wanted to have beautiful "black" babies (he said it). Even he understood that the most basic level it was about the skin we're in.