I think the one thing I see that people have trouble wrapping their heads around is what marriage has become.
It now is simply a contract entered into by two people for what ever reason they want to partner.
No, it isn't simply a contract entered into by two people. All sexual orientations must now be allowed to marry; or else it's the tyranny of the majority stripping civil rights away from a minority, remember? It now may be more than two people (the Brown's brief to Sotomayor is due any day now). The 14th Amendment can't play favorites.
I think it's funny you said
"entered into by two...for what ever reason..." What if their reason is three? Or five?...
"what ever reason"....
Also in Obergefell 2015, Justice Kennedy expressly said that marriage is about more than two people anyway. He said it strikes out and affects others in its midst and society in general. So saying, children are also implicit parties to the marriage contract. In fact they are now expressed parties to the marriage contract since Kennedy largely justified Obergefell because of what he called "benefits children derive from marriage".
And every person since the dawn of time has known anyway without speaking that children are implicitly part of the idea and legal concept of the word "marriage". It was in fact created precisely for THEIR benefit and not the adults involved. Otherwise people would've been happy just having sex with whomever, providing food for whomever, whenever. The trouble is that orphans or wards of single mothers (usually, but sometimes fathers) would starve to death from a free love society. No man would feel bound to them to provide where the mother could not; and vice versa. So marriage was created, for children, to provide them with a steady mother and father so that they didn't fall burden to the tribe or die from want.
This "new day and age" doesn't eliminate the need for complimentary gendered parents. They are still necessary for the self-esteem and mentoring; particular of children of the same gender as they. And since children always come in two genders and so does the society they'll eventually have to fit into, BOTH genders as parents are THE primary benefit of marriage to its implicit partners: children.
So it isn't so simple as you say. There are others involved. And for this reason, Obergefell is going to get a second look. It has to. It's institutionalized child abuse using a contract; which is forbidden by laws present since the 15th century we derived from England.