They, like a lot of people, confused accents with intelligence, and stereotyped whole populations based on rumors.
I grew up in the Deep South. I went to one of the best high schools and one of the best universities in the USA, both in New Orleans. I designed flight hardware for the S1B moon rocket and the C5A Galaxy while I was still an undergrad.
People are leaving Pittsburg for Texas and Florida and Georgia for good reasons.
Read "Dispatches from Pluto"
The USA is beginning to recognize and respect the South. There's more to life than a Boiled New England Dinner and a lot of failed cities.