What doesn't Judge Walker's ruling on Prop 8 exclude?

This question is intended to provoke, so it has to be extreme, and it came from a recent side article in this month's National Geographic. The cover story is about King Tut and DNA analysis done on several mummies in his family tree exposing incest. This provoked the side bar article on royal incest around the world. It has been practiced in many cultures for a variety of reasons. And it did, generally, leave the children worse for the genetic overlap. One anecdote was the practice among Hawaiian royalty who accepted Christianity, but rejected the Bible's prohibition on incest. Leviticus 18:6 "You must never have sexual intercourse with a close relative, for I am the LORD." Lev. 18:7-18 continue on with all the possible ways to violate God's rules for life. I call them rules for life, because he does in verse 5, "If you obey my laws and regulations, you will find life through them. I am the LORD." There is also Lev. 18:23 where God forbids bestiality and before that Lev. 18:22 in He clearly condemns homosexuality. That's why, in dialogs with gay believers, we conservatives tend to question if they also tolerate incest and bestiality, because God also mentions those perversions in the same breath. I know it offends homosexual believers to be compared to those who partake in incest or bestiality, but I am no worse than God in that case.

Now I know that my gay brothers and sisters in Christ condemn incest and bestiality, but on what basis. If the incest is between consenting adults, much like their excuse for homosexuals, then why do they condemn it? On what basis? Robert Gagnon makes the same case in 4 parts here, 1, 2, 3, 4.

I tend to leave the larger political discussion alone on the Umblog, but my provocative question, does involve those who don't claim submission to the Bible as a rule for life. My question is, can Walker's criteria outlaw gay incestuous unions? There would be no risk of children being conceived. Ostensibly, the union would be consensual. So what is the objection? It sounds gross, but the disgust or offense of the majority is no longer determinative in our legalities of sexual ethics, nor, according to Walker, is an appeal to religious ethics.

My fellow believers who want to pursue homosexuality reason that God no longer wants them to suffer, like he did the Israelites for 1500 years. God, apparently, softened up over the millenia, and, perhaps, His commands are not the path to life, contrary to Lev. 18:5. And if they aren't, what prophetic authority do they have in the realm of sexuality? What are the limits?

What if God is right? What if life is diminished, like in any other sin, if it is led in defiance of God's word? Might the suffering entailed in denying homosexual expression be less than that of embracing it? Is God trustworthy?