in japanese manga and animation about world war 2, there is a style that is sometimes used. Characters important to the story are drawn in a more western style to make them stand out visually from the others. Characters that are unimportant are often a bit like those on American posters from that time where the appearance of Japanese soldiers and citizens was exaggerated, the color of the skin, the eyes or the area around the mouth. a kind hearted soldier who is unimportant is drawn in a similar style only cute and someone evil like a yellow monkey. it's okay if a japanese art director uses this style, but if a white or black american used it, it would also be seen as offensive. And Japan, unlike the black slaves of that time, did many cruel things including taking slaves themselves. rap songs are sometimes offensive and controversial probably because it sells well and the n word often is just another word for homie or brother. I don't know the exact story behind it either, but if it's used in music by black artists for a reason, to look cool because it sounders more edgy than homie or to appeal to a certain audience, why not just accept it? it's their word that only they can use if they choose to for whatever reason.