Good questions.
Should be noted that “African American,” if it had a logical meaning, would refer primarily to immigrants from Africa who had become Americans. Same as we refer to Italian-Americans.
For all other groups such designation loses force each generation, and before too long they’re just “Americans” with funny names.
It would also refer to anybody from Africa, which would include Egyptians, Libyans and white South Africans.
But what they mean is a racial term, not a geographical one. I wish they’d just say what they mean.
A very white friend of mine who teaches History in Middle and High School is sometimes challenged by Negro students who tell him he couldn’t possibly know anything about Africa and African Americans. Troy then tells them intensely that he is more African than they could ever be as he was born and raised in what is now Eritrea and what do they know about anything African, anyway?.