I’m curious as to what the OP catholic1seeks considers to be marriage?
Reading through the posts I see a theme that stresses the idea of “whomever I am attracted to, that is my marriage”?
I think that you are almost there when you note that throughout the ages most people have been heterosexual and thus society formed around the idea that marriage should be heterosexual. Certainly, society was built on and around the family.
Where I would disagree with you is that so called “homosexual marriage” gives nothing for society to form around at all. It is true marriage, natural marriage that is ordered towards procreation which builds society. It acts as a sort of cornerstone around which the rest gathers. The father sticks with the pregnant mother and the two rear the children together, coming up with various laws and protections for the good of the family. Where you would say that society grew around this idea as a matter of majority, I would say that society grew around this idea as a matter of necessity.
One might argue that families form outside of the marital bond. For instance a child that has been orphaned for some reason may find a home in another family’s house, be picked up and reared by an individual, etc. but I would say these “opportunistic” families happen only POST-society. Actual marriage and the rearing of children, being the cornerstone of society itself, come PRE-socity.
To say that two men are “married” is a misnomer and considered sinful for the very reason that it confuses what a stable society is built around, that being the natural family.
Where I think your true concern is coming from is the fact that those with same-sex attraction are still human and deserving of a place within the Church where Christ died for us all. And this is correct. We have all sinned and fallen short of the glory of God (not my words, but His) and though none are deserving, He still wants us all there. There are people that have sex outside of marriage, get divorced and remarried, and it seems like the Church does not bat an eye at those.
But in actuality, the Church does speak out against these things. The problem, in my humble opinion, is that these things have been so normalized by our culture that the Church, when it does speak, gets brushed aside and muffled out by the culture giant that is this world. And this is the what we need to pay attention to. The world is attempting to normalize same-sex attraction, because as soon as the culture giant of this world take it in it becomes very difficult to evangelize against it.
But the truth is that same-sex attraction, whether genetic or not, is disordered towards what it means to be a truly stable human family and community.