It's not me who "doesn't get it", it's you.
Like it or not, this is no longer " a Christian country" where common sense prevails at the ballot box. We've elected a bunch of narcissistic idiots and lawyers to public office who will do whatever is popular and gets them re-elected.
Here in California the ONLY thing that got the "marriage between a man and a woman" clause successfully added to the State Constitution was the minority community -- Blacks & Hispanics. The Mormon Church did some in promoting it and Mormons became the primary target for a gay backlash, but that was only because gays didn't want to get called "racists". It was minorities who were the real numbers here in passing it.
But the demographics suggest that this will change in just a few years as a generation dies off and a new generation takes its place, because younger voters don't really care who "marriage" is between.
You can't hold the line with populism anymore, because the masses are against you.
The only reasonable solution is to take "marriage" off the table for government. We all get the legal protection of something like "a domestic contract" between two consenting adults and "marriage" stays where it belongs -- in the hands of the clergy and the private sphere, which is the only place that really regards it sacred, anyway.
Sure, fighting against legal recognition of homosexual "marriage" is tough, but it's doable. And there will always be enough people to stop the other nightmare "marriage" scenarios I listed if we put it to a vote. On the other hand, if your insane approach was tried now, we would immediately see homosexual "marriage", polygamous "marriage" and any other imagined kind of "marriage". That's not slouching towards Gomorrah, that's racing towards it!