Why does my boyfrend think it's ok to say the N word just because it's in a song?

We were listening to Kanye West's golddigger and you know the part where he says "I aint saying she a gold digger, but she aint messing with no broke ....." uh yeah he's white and it felt weird for him to say it. I don't even say the word. He's not racist at all I guess he just thinks it's okay to say it, how do I let him know it's WRONG.