So, let me introduce you to my ‘waiguoren’ friend here in LA. Right, the local is the foreigner.
And since it is a place and not a race there are plenty of white Africans out there, same as there are plenty of black Europeans out there. Calling people who have never been to Africa "African American" just because they skin is dark is just plain racism. They are dark skinned Americans and has nothing to do with Africa.
If you think it is wrong for white Africans to call themselves Africans then how can white Americans call themselves Americans? Similarly when I talk to dark skinned people in Europe they call themselves Europeans and not Africans. When they talk about their "race" they say they are black or brown, because that is the only thing separating them from the other people.
Dark skinned people from Europe are Europeans for all means and purposes, just as white Africans are Africans for all purposes. The "race" that you mention is a very recent development, and is an American export that is mostly confined to Europe alone (and mostly Western Europe). The Africans I've met and worked with often fumed at the whole colour-based distinction. They would rather be identified by nationality, and then language-based ethnicity (Zulu, Xhosa, Amheri, etc). And no, it's not that "anyone can see that they have dark skin", there are pretty clear racial distinctions based on skintone too (light-brown vs dark brown, which was part of the basis for the Rwandan genocide).