But you yourself state that "she should have had the common sense to not use it," so clearly even you understand that you shouldn't be saying this word out loud if you're not black. Ever. A lot of people think they can get away with saying it - they can't and they shouldn't. In this case, the white woman saying it is her lack of consideration and awareness; that she needs to think before she speaks, because as you have demonstrated, she also knows she shouldn't be saying it, ever. If that's something with no exceptions, then why is she saying it?
Kendrick is not perpetuating casual racism here as, well, he's not doing anything racist, but rather pointing out ingrained casual racism of American society by way of carelessness. He's using this incident (at this woman's expense) to make a point about the lack of awareness of non-black people around important black subjects. As previously mentioned, everyone knows it's not okay to say the n-word, ever, but by saying it here, this woman is employing something of a "well, this one time is okay" mentality. That exemplifies how racism is not just open bigotry, but also stems from a lack of care and consideration.
By inviting someone to sing the song, you are inviting them to say the lyrics, yes. But they should also have the consideration to realize their own actions as they're about to commit them, such as violating the golden rule of the n-word as I've stated so many times before. You said it yourself: the woman - the entire audience - knows the word and knows the implications to saying the word and that they shouldn't be saying it. Again, why are they trying to get away with it, then? The right act would not be to act with careless abandon and figure it out later, but instead to maybe ask ahead of time if what you're doing is okay. It is vehemently false to suggest, as you did, that "you're literally telling me to use it but getting mad when I use it," because no one told her to use this word. In fact, society deems that you absolutely shouldn't use this word, but somehow people think it's okay to do it anyway.
People need to stop running around with this initial mentality that everything in this world belongs to them until it doesn't.
