The whole thing comes back to “Essence Before Existence”, a philosophical notion which took root in the 40s and gained traction in the 60s. The idea is that one can determine one’s own essence and that act of will takes priority over “existence”, or the rigid physical conditions we were born into, which is another way of saying reality. Hence, if we want to be something badly enough, be it a different sex or race, that’s what we really are.
Black and White, are now basically cultural constructs, rather than based on skin color.
A person with black skin who is ambitious and applies themself, and is a good family person is considered “white”.