Some of the confusion comes from African-American essentially being an ethnicity. There is a shared culture and heritage, but in addition to the normal aspects of an ethnicity there is the element that people from the dominant American ethnicity (white people) can put people in the African-American ethnicity based on how they are perceived.
Like a black person from Nigeria has very different experiences than a black Amercian, but black people from LA and NYC probably have a lot to relate about.
Besides which, the US as a country has put 100's of years of effort into making black a race through the force of law and through societal pressure.
I wasn't going to make that last point today but yes, black race was for centuries a legal construct in addition to an ethnic one. The American concept of race doesn't travel well.
Like a black person from Nigeria has very different experiences than a black Amercian, but black people from LA and NYC probably have a lot to relate about.
Besides which, the US as a country has put 100's of years of effort into making black a race through the force of law and through societal pressure.