Where I’m from, it is. If the census bureau actually counted religion, you would be able to see this pattern play out.
And as I laid out what I had originally put up here (and decided to make a private one instead), Catholics did have an influence in the antebellum South, far out of proportion with their numbers. The region was not a incubator of anti-Catholicism the way the North was, and many of our generals in the war were of Catholic extraction. Beauregard, Semmes, Cleburne, Bragg, etc. The Deep South was populated primarily by people from the Carolinas, Virginia and Maryland, and by in large, the people who came from Maryland were merchants who came to the cities to make a buck as cotton factors. So, by default, they brought their Maryland Catholicism, which was essentially an establishment religion, with them.
But you have just illustrated the difference between high and low church religions. High Church denominations tend to have more formalized ritual, more heirarchy, etc. And they tend to call their clergy priests. Low Church religions draw more from Puritanism and Calivinism, and they tend to call their leaders pastor, and there is not as much of an emphasis on theologically training among many Low Church believers as their is among high church believers.
It’s actually a good generic term to describe differences in Christian practices, but, in the South, religion has always had a component of class mixed in.