I don't get why people make such a big deal about this. No one in the United States has ever advocated for the rights of people from the African continent. They fought for the rights of those who were brought to America as slaves 100s of years ago and have faced systemic discrimination ever since.

For a black south african, you could argue that their skin color makes them prone to racial profiling, that they are lumped into the people of African descent we deliberately discriminate against and therefore deserve some extra help/affirmative action to compensate for that.

If you're a white South African in the United States, and you try to put your race as African-American to try and benefit from affirmative action, all you are is a cynical pedant. Furthermore, given White South Africans history of subjugation, genocide, and apartheid against black South Africans, you would literally be asking for advantages as a descendant of racists that are supposed to be people who are descendants of those oppressed by racists.