Surely you can see the example though dude. I wasn't being 100% serious.
Surely the anger comes from the fact that the word has been used to describe (by various british ignorami) anyone who looks vaguely brown...
OK, another example: I call my friend a saaathern caaahnt. He is southern, he doesn't mind, he is my friend. If someone else who he didn't know called him a southern c**t, he might well be offended. (By the way, this is just an example - don't take it too literally!)