The Bible is the standard many of us go by for what is right, wrong, traditional, or offensive. God did not ordain marriage for the benefit of "all" as you put it, else we could marry our relatives, children, dogs, sheep, etc...
Society, both the religious and non-religious, are taking a stand and are largely in vast agreement, that homosexual marriage is an offense to this society. Gays are free to live as they please, but marrying and the adoption of children is what is at issue. Only Democratic politicians and activist judges feel otherwise. Even the blue states voted down gay marriage in the last election.
You are on the losing side of this one. And that isn't likely to change except for the mischief judges can do.
Hey Luke---did you read the linked article?