I personally think it is alright to use them whenever wanting to - even to shout a racial slur about Jews to a Jew. People who take offense by being called "whitey", "nigger", "chink", etc. are pathetic. It is ridiculous to take offense from an insult directed at a whole racial group and not to oneself, as one's race does not = oneself.

For the very same reason I think it is pathetic to take pride in one's race or nationality. Why be proud of something that others but oneself has achieved.