Moeller isn’t saying Christians should accept gay marriage. He’s saying the heathen world is going to accept it as normal and he’s right. He’s also right in saying we as Christians should prepare for how we are going to deal with this to insure our Churches and especially our children are not infected with the spirit of acceptance of this worldly perversion. Just as God warned the Jews to resist the idols and false religions of those around them so too are we called to resist and not succomb to the unholy spirit of this world we are just visitors in. And now that unholy spirit seems to include gay marriage.
As Christians we deal with it the same way we are dealing with abortion. We oppose it, consider it a crime, march in the streets, push for changes in the law and elect our representatives accordingly.