A handful of cities (NY, Philly, DC, Oakland..) have bad fans, while most cities are cool.
...I have experienced it, in stadiums like Philly. having lived all over the country and working with people from all over teh country, I think I have a pretty good perception that the AVERAGE NY/New Jersey person is more selfish and obnoxious. THAT's average, means there are buttholes in every city, many of them, it's just that there's a much larger percentage in NY.
So, not ignorant. The word you're looking for is: perceptive.