In comparison to other African offshoots?
Are AA more faithful to their own than Jamaicans, Ghanians, Brazilians, British? I don't understand why we are viewed as some stagnant. not varied offshoot of our predecessors? We are our own unique Black population. Not sure why other Black diasporas are allowed the privilege of saying they are more "different" and thus can prescribe to self-hate.
other ethnicities to include everyone not just black ethnicities
I don't understand your last sentence but I would say there's more homogeneity in other black ethnicities compared to black americans (I do not like the term African americans as that should be reserved to AFricans now living in America lol). This probably has to do with the status of America as being more of a melting pot then most other countries with black ethnicities (outside of maybe Brazil)