Black people make a wayyy bigger deal out of white people saying kick someone's black ass more than white's do. Hell you can call us cracker, whitey, white trash ect... It doesn't really bother us. The minute a white person points out a black american's race it turns racist for some odd reason....
Read what you just wrote. It doesn't bother you. Cracker is a slave term, ie One who cracks the whip, or slave driver, overseer. White Trash, white people use that term all the time to describe rednecks, because if your white, you are not suppose to be poor...your white.
Kick that black man's ass is not racist, now if one says "kick that n*****'s ass", then it has another connotation to it. It's meant in a mean and spiteful way.
I put it to you like this if someone off camera had said that, both of them are n*****s. It's a equal opportunity word to me.
Basically black folk get upset because words have history, unless you are subjugated to demeaning words, actions, deeds, policies, laws then you wouldn't understand.
Now I ask you which one of those to you, honestly is a n****? Which one do you most associate with the word. And ask yourself why, now that my friend is racist.