“Marriage predated the Catholic denomination, and they aren’t going to become the state church and control our lives, anytime soon.”
I’ve never advocated that. If you wish to make yourself a member of a church and observe it’s policies, then that is your choice.
Your religion or lack of it has nothing to do with being legally married in America.
Here is law from North Carolina “” After the American Revolution, couples could choose a clergyman or a Justice of the Peace to solemnize their marriage. The laws of 1778 provided that, in addition to the Anglican clergy, “all regular ministers of the Gospel of every Denomination,” as well as Justices of the Peace were “empowered to celebrate Matrimony””