No, I don’t know that. I have seen the assertion (and with it the assertions implicit in replacing “libertarian” with “social liberal”), but have not seen any proof. Just a lot of noise and chest thumping about it, as if saying it often enough makes it true.
You don’t know about the religious divide between liberalism and conservatism, as in the more religious someone is, the more likely they vote Republican, and the less religious, or non-religious, the more likely they are to vote Democrat?