I'd say that it has been used as an insult, a threat, and a weapon for years.
I few years ago, my wife and I went to a Waffle House, and it was VERY busy. There was a black couple ahead of us. When the counter cleared, we were all seated. The waitress mistakenly thought we were next, and started taking our order first.
The black woman immediately took umbrage, and angrily said, "You need to be written up!" They didn't exactly say racism, but the language they used made that accusation clear. Instead of telling her that they were next, it was massive butthurt and accusations.
We before then, we had seen her working several times, and I never saw her treat black customers differently. I specifically remember waiting to place our order and waiting while she refilled the drinks for black customers at another table. I remember it because I was starving, and the delay frustrated me.