It's unfortunate that there is such bias towards the southern US. I am amazed that people confuse good manners for ignaornace. Maybe they had manners thirty years ago in the North east USA. Very provincial thinking.

1 I've lived in the hills of East Tennessee all of my life, about
   ten miles from the border of Georgia and Alabama, and about an
   hour from North Carolina.
2. The accents are different, in just the distance of ten miles.
3. I spend a lot of time in New Haven (CT), home of Yale University,
   and the racial and religious strife is worse there.
4. Poverty, ignorance, and racial emnity are not endemnic to any
   geographic region. Taking "shots" at the south is as intolerant
   as previousr generations taking "shots" at the "Irish Problem," or
   the "Negro Problem," or the "Hispanic Problem."