It has been said that the fanatic is the one who redoubles his efforts while having lost sight of his end.
So reminds us Doug McManaman in his (Catholic oriented) essay On the Importance of Taking Oneself Lightly. He goes on to note:
I have seen a tremendous redoubling of efforts on the part of many Catholic teachers in recent years, engaged as they have been in strategic planning of job action for this, for that, and the other thing, all accompanied by a manifest loss-of-sight of the end of their vocation as Catholic teachers of the baptized.
Humans need a purpose to live, and some religious people deep down do not trust that God has given them sufficient purpose. Even among these, some fear that they will not be around to watch the wicked get their just desserts. Theirs is the sin of self-importance.
The LDS focus opposing same-sex marriage is a fixation on means, not ends. As a practical matter, the most probable end in forcing gays to choose between their immanent orientation and God is to prematurely kill their faith in God, or at least to keep infantilized their moral conscience.
Biblically, the usual course of events is a lone voice crying out from the wilderness, followed by earnest exhortations for the wicked to change their ways, which is always ignored, the righteous withdraw, and God smites those left behind. This leaves a clear moral example for those coming after, that free choice has consequences.
We are in uncharted waters now, where the "righteous" decline to withdraw and let God do the smiting. This forecloses on free choice, and deprives those coming after of any cogent moral message.
Or to use another parable: what if the wheat had decided that instead of waiting for the farmer to separate out the weeds after harvest, they are going to crowd out the weeds from the field themselves, not only usurping the farmer's prerogative to decide the weeds' fate, but forestalling the possibility that a weed may choose before it dies to become a wheatstalk.
I believe it is this second aspect that is ignored among the religious. You cannot save a sinner by preventing him from sinning, you only strengthen his resolve to sin. If same-sex marriage is so far beyond God's plan, will it not prove its fruitlessness in the fullness of time? Does the wheat not have enough to do in producing grain, or must it also weed the garden?
If the real goal is not the voluntary choice of chastity, but chastity itself, then we would be better off neutering those unwilling to marry the opposite sex by some age cutoff. Would this not better serve God's plans for humankind? By eliminating sexual desire, do we not eliminate the sin? Is the elimination of sin itself the real goal? Or has our willingness to be the instrument of God's will metastasized into an insistance on our being that instrument? Do we just need to be needed?
Maybe we should all stop playing God. One day the field will be harvested. If the weeds are not keeping the wheat from producing, maybe we can afford to let both coexist until the final winnowing.
Or is the real problem that you don't want to be the wheat, and would rather be the farmer? If God had just wanted us not to be wicked, he could have just created us all heterosexual.
Do you have the wisdom to play God? Judging by the LDS involvement in Prop. 8, somehow I doubt it. Maybe you should just stick to being wheat and stop uprooting the weeds, before the entire field is barren.