Why is that sad? Race is nothing more than a social construction. The one drop rule has been more of a positive for black folk in America than a negative (in comparison to other slave holding societies in the Americas).
Just look at Brazil or many hispanic countries where there was no one drop rule. We here have never had as much beef and hatred within the black community as they have down there. In those countries you got people with dark skin and nappy hair (who would be black in America) discriminating against darker skin, nappier hair black folks worse than even whites.
Blacks in Brazil and Latin America have been divided and conquered. Even though nearly 50% of all Brazilians have predominantly black heritage, less than 10% self-identify as black. Thats because in Brazil there was no one drop rule and you got 10 different races in that country based on skin tone. Just think about it. America is less than 14% black, yet we have a black president. Brazil is 50% black (by American standards) and yet every leader of that country is blond hair blue eyed cac.
The fact cacs in America looked at blackness as a stain and made it so that anyone with any black heritage is totally black has been a blessing in disguise. We have a more united black community here. And a community that stands up together where its someone light or dark skin being discriminated against. We look at our interested as being the same because regardless of how light or dark we are, we're still all n1ggers to the white power structure. That is alot better than Brazil or Latin America where you got light skin black folk thinking their interests are not the same as darker skin folk because they are looked on more favorably by the white power structure.