That word is a "racial slur." Every ethnicity/race has been given a racial slur by another race. I'm not going to list them but just about every race has a racial slur. Blacks, Whites, Jews, Japanese, Chinese, Indians, ect., all have racial slurs. So the real question is, "why is someone offended by a racial slur?" If you don't know the answer to that then I am not going to waste my afternoon explaining it to you. You are so far from a basic understanding of common sense that I'd be better off .... (insert phrase here).