Here’s the argument, transcribed almost exactly, so forgive the speaker the stop-start nature of the prose.
What do you think about that example,… the concentration camps of Nazi Germany. Does our moral revulsion at those concentration camps, … Is that because there is an objectively real fact about the matter?, that treating people that way is wrong,…?
Say Hitler had won the war, and we now lived in a society where because of that and the propaganda, everyone believed that anti-semitism was good, and gassing Jews was fine, would that mean then that that was simply the morality that we accept?
Is morality simply, at the end of the day, what society thinks about a matter? Or would it still be wrong? Even though nobody thought it was wrong?
Would it actually still be wrong, because we can be wrong about moral facts?
And if that’s the case, does that suggest that there is a moral dimension that isn’t part of our natural world, that somehow transcends it? Could this be the evidence for god…?
NonStampCollector investigates that hypothetical question. I won't copy his post here (though I'll post the video, if he makes one), but it's quite good. Check it out.
Edit: Those links are broken. Apparently, NonStampCollector has closed his Freethought Blogs account and I can't find the post elsewhere. Thanks to a comment by a reader, here's his video response, which makes the same argument: