I repeat, Crow! If a fellow Yank utters said epithet, no problem. If some snot-nosed Euro-Yuppie follows suit, there's a problem:-)
If an African-American jokingly refers to his compatriot by the infamous N-word, ok! If I or another Caucasian were to, definitely NOT ok.
Germans have a long history of looking down on the Poles as a farmland of slow-witted dullards, fit to feed and mass-produce for Germany, but for not much else, if anything. Same view of Denmark. A land of butter, cheese, dairy and pretty girls, but take it seriously? You must be kidding.
This once pervasive attitude has largely changed, except perhaps among the Pegidists.