I cannot speak for the rest of the country, but I know in Connecticut the following was hardly unknown as of the mid-80s:
“There are black people and there are ni**ers. The guy who ripped the radio out of my car and smashed my window is a ni**er.”
So, it is now impolite talk, but hardly meant as a slur on the entire race. It is more along the lines of living down to the racial stereotype. I wouldn’t be surprised if the same thought process happens in New Hampshire, which has relatively few black people, but would want a way to distinguish ordinary Americans from thugs.
I think you made an accurate representation of the usage of the word these days.