Well this is my opinion so please don't debate me on it. If it doesn't make sense to you just KIM or neg me. This is my opinion as a black man living in america. I can't speak on Africa or anywhere else so don't get offended.
Being black is something no white person can truly infiltrate or even understand.
So we are really a deep mystery to them. When white people aren't included by any societal means or norms by other cultures especially black then they will get
offended
curious
irritated
angry
Because they think being white would give them access to any culture or any acceptance and for most cultures around the world whiteness will get them in...when they do try to make that connection with black people and we will usually shun them or keep distant then their white comfort and white fragility gets low.
So they pretend to be black to TRY to make some sort of weird offensive connection because being white by default will never ever work trying to gain any acknowledgement or simple connection with American black people.
They think by imitating these stereotypes created by them in regards to what black people are in their minds that they somehow can make a social connection to us which is way far off or even more so dating one of us and STILL even then they won't make that connection to our black world and mind even if they decide to have sexual access to our bodies.
The Black World (Mind and Experience) is something nobody can infiltrate nor access if they are white especially. (in my opinion) it is something so unique and looked upon with disdain, arousal, curiosity, and wonder because being black is literally counter culture.