I don't think that the names were chose to to perpetuate
stupidity on the part of southerns. It was more the writers' thoughts on what would portray what THEY consider to be a southern name. LOL. Remember Petticoat Junction with Betty Jo, Bobby Jo, and Billy Jo? Lil Abner with Daisy Mae?
I don't think anyone considers Oliver North or Oliver Hardy to be either southern or stupid. Same goes for Peggy Sue, in the movie "Peggy Sue Got Married". In my state, we have a U.S. Senator by the name of Tammy Baldwin. Definitely not southern, or stupid.
Perhaps the writers need a better education.