Southern Appalachians have been ridiculed since the country began. In fiction, they're usually depicted in a cartoonish manner. The region is poor, and very suspicious of outsiders, so there's a sort of 'us versus them' situation. They're easy to poke fun at.
Barbara KingsolverCodi: Gives you the willies, doesn't it? The thought of raising kids in a place where the front yard ends in a two-hundred-foot drop? [referring to cliff dwellings] Loyd: No worse than raising up kids where the front yard ends in a freeway.
Barbara Kingsolver