Same sex marriage is not stated in the constitution.
The concept of liberty is stated in the fundamental ideals of the United States of America.
So why not give people the most possible liberty? Going back to my idea:
"So, with all of this in mind, I see the best thing to do is remove marriage from the government. With marriage completely unregulated by the government the people who don't want a [what they would probably considerable] credible organization recognizing 'marriage' between homosexuals get what they want. Marriage and the family is as protected as it is ever going to be. And people who use the reason of freedom get what they want. The government has no control, a church can marry two homosexuals, it can marry polygamous (for you Mormons out there), bigamy, a woman to a dolphin (which actually happened recently in another country), anything. That being said, it doesn't even have to be a church that marries people."
It gives a lot more 'liberty' than your idea and it is against civil same sex marriage.
As for an 'ideal', an ideal does not outweight the Constitution of the United States. I ask you to use an argument that actually holds legal weight.
Thats an extremely narrow view of equal rights.
It's the view of the Constitution, the view of the loosest possible interpretation giving the government the most possible power that can be given.
Thats like saying in the 1800s that anyone had the right to own a slave.
The government ruled that slaves were property (Dred Scott case) and since slaves were property, the government could not take them away without due process. A lot of people did have the right to own what was considered to be property.
As for saying anyone in the 1800s had the right to own slaves would be completely ignorant of history. Where slavery could and could not be resulted in things such as the Missouri Compromise which means in itself only people below the southern boarder of Missouri could own slaves, and slavery would not be permitted above it. And the history goes on, but I'm just using this one example.