What else matters?
Many posts have hinted at it; yours said it best.
And for you atheists, divine decree need not mean God, but the natural order. Solar systems revolve around a sun; galaxies around blackholes. Society revolves around families. Marriages are composed of male and female, just as life on earth is composed of carbon, hydrogen, oxygen and nitrogen.
In nature some things are constant throughout.
Citation, Please. I don't think you can find a biblical mention of gay marriage let alone a proscription against it. One can reasonably infer that gay sex will occur within a gay marriage and one can state (against some arguments perhaps) that the bible proscribes gay sex but there is no biblical law against gay marriage that I am aware of.