You've missed what happened in Obergefell. The SCOTUS already destroyed marriage as a civil institution. By their decision there is now an institution in all 50 states falsely called "marriage" which is not marriage. Whether it optimally takes the form of the bill in Alabama, or some other form (Fr. John Whiteford proposed each state creating a "community property registry" and a "registry of potential births"), the correct response is not to accept the Newspeak version of "marriage" which means whatever the Federal government says it means, but for the several states to refuse to participate in the sham the SCOTUS has foisted on us.
The solution is to ignore the lawless opinions of a court that has made itself illegitimate, not to finish destroying the civil institution of marriage for them.
This ill-advised strategy jumps out of one ditch right into another ditch, with the same outcome either way: marriage is destroyed.