is a social construct.

As such...different societies define the parameters for race differently.

In the U.S. ... we follow the one drop rule. And so light bright damn near white is considered Black. This is largely because whites are the overwhelming majority here and as such they can ostracize anyone with any amount of black blood.

In places where whites live, but are a smaller number they will "include" more persons of color within the circle if you will. So in Brazil or South Africa people will be stratified much differently. Its not just Black and/or white. Mestizos, Mulattoes, Colored etc will be intermediary designations because the white folks in those countries know they cant totally ostracize everyone with black blood because they would end up getting eaten.

So its not really that Americans lack nuance when it comes to defining race.

Its the power structure needs its racial classifications to achieve something different.

Race aint real...but has real implications.