You should see the History Channel's, You Don't Know Dixie! They go into the reasoning behind the South's attachment to the Religion. In fact, Clintonista James Carville actually narrates that particular section and does a good job of it.
For those who have faith, no explanation is neccessary. For those who have no faith, no explanation is possible.
St. Thomas Aquinas
If one turns his ear from hearing the Law, even his prayer is an abomination. Proverbs 28:9