There is no way of proving this, but my best guess is that the GLBT forces in the church are more about obtaining official moral approbation than practicing deeply committed faith. It is quite a coup for GLBT forces to have convinced the progressive leadership of such denominations to turn traditional religious teaching on its head in the span of one generation.
Gay organizations have been very successful in redirecting the culture regarding their lifestyle. Using the progressive definition of "tolerance" they have effectively silenced disagreement by labeling any opposition as bigoted. Mainline churches once were good stewards of Biblical morality. Now, in the name of tolerance, the tables have turned with mainline denominations serving as important support in favor of sinful lifestyles.
One example of this cynical agenda was revealed in the comment of San Francisco Theological Seminary (PCUSA) student Doug Hagler. Hagler is opposed to the carefully thought out, Scriptural arguments that professor Robert Gagnon (Pittsburgh Theological Seminary) has made for traditional teaching.
"[N]o matter how good [theologian Dr. Robert Gagnon's] arguments are, the conclusions he comes to are patently bigoted, so I reject them regardless of what apparent veracity they may have. Frankly, if Jesus Christ pried open the skies and leaned down into my living room right now and said 'Doug, it is a sin to be homosexual,' I'd say 'Okay Jesus, that makes things simple—I'm not Christian anymore. Now go away.'"Hagler puts Scripture third in terms of authority, right after reason and experience. The problem here--notwithstanding its departure from Reformed belief--is that human reason and experience are utterly subjective. If God is not objectively revealed then God becomes an imaginary construct with a strange resemblance to the thinking of the one making up the construct.
The truth doesn't matter, if you feel that a particular sin is right, then it is fine to lead a Christian denomination to destruction. PCUSA seminaries are preparing people whose ordination has been made possible through the passage of the PUP recommendations last June. Your own presbytery may not endorse or ordain them, but if just one presbytery does, such a view has been officially welcomed into the denomination.
Such an ordination will be a de facto denial of the Lordship of Jesus Christ. The sovereignty of sinful human beings is worshiped above all else. It is no wonder that the PCUSA and its sister mainline denominations are so unhealthy and so confused.
Keep praying--keep the faith,