Someone made a good point above. My co-worker told me today he is only socially conservative. He is OK with gays, abortion, and other socially liberal issues. I didn't fall off my chair, nor did my heart skip a beat. But if he had said "nigger" even I would have been a bit shocked, disturbed, etc. at least to myself.
So saying in so many words, "I'm OK with ripping babies apart in the womb; I just don't want to pay for it." is perfectly fine. You barely even notice. But if someone says, "nigger" we all get outraged or disturbed, at least deep down, as if some major crime has been committed -- even those of us who try not to be, or don't want to be outraged.
Why are people more offended by "nigger" than "cracker", "honky", or common swear words like the f-word? Think about it, it's true. What kind of programming has taken place anyhow?