I submit that there is a difference between the acceptance of homosexuality in the (mainline mostly) church and the acceptance of other, previously unaccepted beliefs and behavior, such as no-fault divorce, unmarried cohabitation, separate entrances for men and women, praise bands with drums, pews with cushions, alcohol, smoking, universalism, the Social Gospel, etc.
It strikes me that in the case of homosexuality, more so than the others, that the Devil is openly and loudly and proactively banging on the door of the church, demanding to be let in. For most or all of the other issues, the acceptance was made (rather more) quietly, one person at a time, one church at a time, one instance at a time.
I don’t recall great debates over no-fault divorce, unwed cohabitation, and other sexuality-related issues. The acceptance came gradually and (more or less) quietly.
Having achieved success with no-fault marriage, the devil has now become more audacious and visible. He demands that the church publicly announce either its denial that homosexuality is sinful, or that take no action against this sin.
In the mainline denominations of the United Church of Christ, Presbyterian USA, Episcopal U.S., United Methodist, and Evangelical Lutheran, Satan has more or less won.
Perhaps... but 'won' what? These churches are hemorrhaging members. They will surely die on the vine as their congregants leave for greener pastures. And it is no coincidence that the fastest growing churches are the non-denominational spirit-filled variety that have no 'confession', but are only and very insistently Bible concentric.
The smaller churches with a congregational structure tend to be more adept at removing heresies by utter collapse. It is the hierarchical churches, which by their hierarchy, are able to absorb heretical doctrine and survive it for a longer period of time... And the more hierarchical, the more likely one is to find institutionalized forms of those very things, because the hierarchy becomes inured to admitting their error.
And the cost of bureaucracy ALWAYS leads to concession. Gotta get them butts in the pews and get them wallets to open up... And so, a compromise in doctrine becomes inevitable.