IMO, the RE definitions of race are consistent with transracialism.
Collectively, tge loudest people on RE says that Race is cultural, and has no basis in genetics.
If that’s the case, then race is more of a collection of stuff you like or something about how you were raised, not who you were born to. In other words, it would suggest that a white kid raised by black parents would be black, and if you are raised by a white and black parent from a young enough age, you are biracial.
But RE will say that race is not genetic, but you still have to be genetically black to be considered black. But if there is no basis for race, then what is the basis for being genetically black?