Though not "black" and "white", I know that some black people do not like being considered African American. There is a difference between someone who has family come over through slave trade, and someone who came to America willingly from Africa.
I can understand why they might feel that way, they had family sold into slavery by others in their countries. They've lived on unable to express themselves for generations, and are culturally different from people from their ancestors homelands.
So being black and calling them African American may not acknowledge what they see as clear differences between the two.
G mostly