Sent to you by moya via Google Reader:
Because it isn't about what offends people. Lots of things offend people. My existence as a trans woman is offensive to some people. Black people having natural hair is offensive to some people. Being offended is just not liking something, it isn't a basis for anything.
The reason why certain words are a problem is not cuz they offend. It's cuz they prop up systemic oppression. They act to influence thought patterns and create a dangerous environment. They're used to tag certain areas as hostile to keep marginalized people out or to keep the oppressors up on the fact that they can act out more if they want to. A place where a white kid freely belts out the word "spic" or "nigger" or a place where a cis guy freely says "shemale" and "trap" are places where violence is far more likely to happen to poc and trans women respectively (as examples).
They dehumanize marginalized people in the heads of the people who use them and dehumanize marginalized people themselves, in their own heads. And they are often used to pass along concepts of negativity to be assigned to oppressed folk.
So a slur is a slur cuz it props up systemic oppression. Not cuz it hurts feelings.