I'm in Germany and I'm also puzzled by how Americans view race. To me, black, white, etc. are just phenotypes, no more important than e.g. being blonde (of course, I realise that some people discriminate based on skin colour). The idea that these skin-colour labels constitute separate "identities" is a bit weird to me.

And yes, of course many African-Americans have certain cultural traits, some heritage etc. that sets them apart, but I would describe that as "African-American" and not "black" because I don't think that a Nigerian or a Sri Lankan would share those traits.

When Donald Trump insisted that Kamala Harris wasn't really black that just made no sense to me.