This is such an easy one to argue if you spend 2 seconds thinking about it. I think people just balk the minute it gets tied into a larger political theory.
If marriage was simply about love: common law marriages would be legal and we wouldn’t be arguing if nonhet people can do it
I want to ban marriage as an institution. Ceremonies should be allowed but there should be no benefits over other relationships and living styles for monogamous couples over everyone else
Ideally this would happen in socialism where private property isn’t a thing so that doesn’t matter either