Specific people might take extra exception to racist attacks for whatever unique reasons apply to their own lives, just the same as somebody might take extra exception to specifically rape jokes but other things are ok... It doesn't even have to relate to something within their own life at all times but can just break down to strong preference or the way they were brought up to have certain respect on certain issues. Everybody's different.

Basically there's no way to make everyone happy and if we stop racist characters and racist commentary/trash talk/etc altogether then we would have to display that same care and treatment to the people who take exception to rape, or same sex jokes, or whatever else really happens to get under anybody's skin. It would pretty much turn into a slow motion domino effect where at first it would seem fine with banning 1 subject but then that 1 subject already being banned would BE part of the argument that helps support the banning of the next questionable subject... and so on... and it snowballs.