"Identities are generally fluid and reflect matters of degrees of commonality and shared experience."

Well sure, and this is what I believe is happening with the Black identity. Unified may have been the wrong word to convey what I mean.

I have zero reason to feel anything like that with a "white" identity, germans being just an example. There is no real anti-white discrimination in a systemic sense like what black people face, so I see no reason that white would warrant a capitalization. There is just no similar shared identity.