Vichy collaborated with the Nazis. The original poster is not saying we should collaborate, but rather, that "gay marriage" as law of the land is inevitable; just as the Nazi blitzkrieg was inevitable. To take the analogy further: if you are suggesting that "gay marriage" will not be the law of the land, you display a mentality like Hitler in his bunker in the waning days of WWII, in which he ordered his followers to believe that the war was not lost as bombs rained down from above.
“you display a mentality like Hitler in his bunker in the waning days of WWII, in which he ordered his followers to believe that the war was not lost as bombs rained down from above.”
This is word for word what Petain told Churchill. Woe if he had taken his advice!