it depends on where you are..
if im around mostly white people, the black guy is gonna get called the black guy, why? cause he stands out and thats the easiest way to describe him.
now if he were white, id have to describe his hair color or nose size or height or weight or level of attractiveness or something like that.
and its the same if im around only black people, the white guy would be the white guy.
its only when you put a derogatory meaning with those words when it becomes a problem.
its like the N word. i dont even have to say it fully, its that UN pc to say it
but to me its just a debased form of the spanish word , negro, which means black.
calling anyone that for me, is just funny, its a funny word..
not an insult. though since i know its insulting to some, so i wont use it. (its neither that funny nor interesting anyway..)
and btw, im white and have slaves in my ancestry (1000 year back, some of my ancestors used to own some other of my ancestors (all white))