When it comes to marriage law same sex marriage is not truly marriage. It doesn’t meet the criteria for marriage. So it is really a legal fiction. You can make it legal to declare yourself to be the president of mars, but that doesn’t make you the president of mars. You can make it legal to declare yourself to be a man when you are a woman, but that doesn’t change the fact that you are still a woman. Saying that you are legally a man does not change the fact that you are fundamentally and naturally a woman. It is similar to marriage. Marriage is fundamentally about procreation and family. Since same-sex relationships are fundamentally not about procreation and family then they do not meet the criteria for marriage.
Now, same sex couples could create all kinds of contracts and committed relationships with one another. No one is trying to take away their freedom to do so. (Even though it was illegal at one time). Nonetheless, such contracts could never have the same end or goal as marriage does, which is family. It is naturally impossible since procreation is naturally impossible.
When you live in a society that is largely secular I think people realize that you are going to have to pick and choose your battles, or prioritize your concerns. Abortion and certain contraceptives prematurely end human life. That is of much higher concern than same sex marriage, which is a legal fiction anyways, and not a true marriage, even if it has some elements of marriage. And no legalization or law can make it into a marriage, any more than a law could make a man into a woman. It just is not reality. Since it cannot fundamentally meet the end or goal of a marriage.
So I guess you could spend your time trying to make it illegal for a person to declare themselves the president of mars, a legal fiction. But you may find your time better served elsewhere. Dealing with the root of the issues may be more effective.