How did the Ku Klux Klan operate in Louisiana despite the large Catholic community there?
You seem to be making the assumption that a person can't be Catholic and a member of the KKK at the same time. They wore hoods so other people wouldn't recognize then.
But historically they are vastly different.
KKK have been overwhelmingly Christian, though I believe more Baptist. What do you mean be vastly different?
Clarify.