Thanks.Christians can't change people's minds and hearts by shouting at them or trying to block their personal descisions. that's weird, and not very productive. not to mention mean and ungracious. Christians are called to be pure, modest, humble, and to adhere to standards of uprightness and Godliness. this includes rejecting relatioships, temptations, and desires which get in the way of one's walk with God. but i wouldn';t expect any out and proud individual to see that as applicable to their identity and orientation, or even spiritually meaningful.
so i'd argue that it's it's best for Christians to live and let live, share the truth when able, and pray for folks. and above all, treat others as you would want to be treated.
Something popped into my head while reading your post - not so much directly from what you wrote, but from thinking about related issues.
Most Christianity in the US is Protestant: they're very big into the idea that salvation is gained through "faith, not works". The interpretation that I've heard many times is that once a person is saved, the indwelling Holy Spirit within that person will express itself outwardly through "proper" behaviour.
I realize that this doesn't necessarily mesh up with Catholic or LDS theology, but in any other context, if you ask a huge proportion of the anti-same-sex marriage camp what value works without faith has, they'll say that it has no value at all.
So... why are they pursuing this course of action? Why clamp down on the behaviour of non-believers? Wouldn't the more Christian (or at least Protestant Christian) position be to bring all people to Christ, and then any issues of behaviour will be corrected by the Holy Spirit? Even if we take as given their position that homosexuality or same-sex marriage are sinful, why take the stance they have?
In the viewpoint of standard Protestant theology and even accepting all the positions on homosexuality and sin, if the anti-same-sex marriage movement doesn't address the core issues of faith, isn't it kinda like "whitewashing tombs", to use Jesus' analogy? What's the point?