As I've often contended, there are two venues in which civil and sacramental rights for LGBT people must be fought: the courts, and homophobic churches the influence of which cannot be underestimated. In the latter venue, peaceful and continual picketing during services of selected homophobic churches in each city or jurisdiction, showing how their false gospel of exclusion is antithetical to the Gospel of grace, faith, peace, reconciliation, and inclusiveness, should be undertaken.
When you hit, or threaten to hit, discriminatory institutions in the pocketbook, we might reasonably expect them to tone down their hateful rhetoric and discriminatory actions; withholding funds, such as removing churches' tax-exempt status, can be a major way of gutting the homophobic rhetoric and actions that exists in many, if not most, denominations and churches, because those churches would then lack sufficient funds to bankroll the prevention of equal civil rights as has hitherto existed. For the Roman Catholic Church and the Church of Jesus Christ of Latter Day Saints, to give just two examples, to enjoy tax exempt status is, in my opinion, a profound injustice!
I am a Christian who is quite theologically conservative, and not only don't I see any warrant to prevent same-sex marriage, or justify any type of homophobia, in the Bible, I am also adamant about the need for the separation of Church and State.
Currently, the Church and the State have become so enmeshed with each other that most "conservative" churches extol as virtues Americanism, patriotism, militarism, and capitalism. Indeed, most of the institutional Church is a handmaiden of the State, and often parrots the ideology of the power elite in secular society, and does so by calling it "biblical."
Of course, nothing could be further from the truth! If anything, the Bible, particularly in the New Testament, subscribes to anything but capitalism, as can be easily seen when reading Acts 2:44-45; Acts 4:32-37.
In any case, it's a profound tragedy that it's quite likely that if you ask the average person to say the first word that comes to his/her mind when the word "Christian" is said, "Love" is not likely to be that word! We're far more likely to hear words such as "sin" and "discrimination," thanks to the perversion of the Gospel of grace (the only Gospel to be found in Christianity) that exists in most of the institutional Church.
It is crucial that discrimination, be it in the religious or secular arena, be taken to the judiciary, and not pathetically taken to the public to win their votes on this or any civil rights matter! And, we must do our best to remove public funding of church and para-church organizations.
After all, if clergy within denominations and churches really have faith in God to provide for their needs, they don't need tax-exemption to help fund their operation!