andy-hughes, //That's a classic chicken-and-egg scenario isn't it? //
No, it isn't. For example, if someone calls a black man 'A black ***', the chances are he isn't going to be offended by the word '***', but by the word 'black'. If however, he were to respond by saying, "Yes, I am black", where does that leave the aggressor? Stymied. His intended insult hasn't achieved the reaction he expected, so there's no point in him repeating the exercise.