I think it is the typical rationalization without much attention to what Scripture says or means. While the biblical stance against homosexuality is not quite as strong as some would like it to be, it cannot really be rationalized away either by appeal to word meanings, cultural changes, social awareness, or by challenging simplistic proof texts. I think it is a classic case of beginning with a conclusion and then interpreting Scripture toward that conclusion.
On the one hand, I think we, especially evangelical Christians, have probably made far too big an issue out of this to the point of becoming unloving and violating the acceptance of people as people, where they are, that Jesus taught and modeled. On the other hand, I am tired of hearing people with genuine and honestly held positions against homosexuality and gay marriage labeled bigots for holding such a position. Both sides need to chill.
I understand some of the medical and psychological evidence of gender confusion or even biological and genetic evidence related to gender identity. But then to argue that it is "normal" and therefore acceptable is a big step in logic. Not everything that is "normal" is inherantly a good thing and therefore acceptable. It is also "normal" for most people to be biologically hard wired to be promiscuous, but we acknowledge that for the sake of society and relationships, that normal condition needs to be controlled and modified. When it is not, it becomes destructive. Most of the other arguments in favor of homosexuality, like some of those presented here, tend to be very selective, sometimes distorted, and in many cases will not stand up to sound logic.
Bottom line for me (and it is a personal position): I am called to love other people with the love of Christ. I am not called to judge people for where they are in their life journey. That is God's responsibility. I think an active homosexual lifestyle is wrong and destructive, like so many other things against which Scripture warns. Yet, it is not our job as Christians to condemn others but rather to model Christlikeness for them, to live as people of God loving others as God has first loved us.
I know and have worked with several gay and lesbian persons and couples. All of them are decent people, and I have tried hard to treat them with equal respect. I doubt if it would help them in a relationship with God if I were to rail against them for their lifestyle. If they would ask, I would openly talk with them about it (and risk being labeled a bigot). Until then, the best witness to God I can offer them is to model for them the love of Christ by how I treat them (Matt 7:12).