The government has to set up some institutions like marriage or else the courts would constantly be clogged with people individually suing to protect their interests. Same goes for a lot of libertarian arguments like getting rid of he EPA.

that isn't why. In fact marriage legalizes pedophilia in a lot of cases (missouri was the destination wedding spot of child brides until SVU did an episode about it in like 2018).

From what I've seen is the argument is the supreme court isn't going to over turn it so there is no reason to pass a new law. But they said the same thing about abortion.