The "Moral Argument" for the existence of God is known in Apologetics. To say it is wrong without an explanation is to lose the argument. I would have to call it an ostrich approach, but if some skeptics want to use this ostrich approach I'll be glad.
Actually, Doc, what happened is that you made the argument for us...
See, (as others have already pointed out), you stated that even if the Axis had won WWII, at least some part of the population (this is what
most means, btw) would believe the Holocaust was a bad thing. Since some people (even if it's just 1 person, really) believe the Holocaust was a bad thing, then morality cannot be absolute.
ETA: And we can even take this the other way. There are some people
right now who believe the Holocaust was not
that bad (we call them Neo-Nazis, generally). Since some people (again, even if it's just 1 person) believe the Holocaust was not evil, then morality cannot be absolute (unless by absolute you mean absolutely no overarching basis for morality).
Absolute morality would require EVERY single person on this planet to have the exact same sense of morality - and, well, truth be told, we don't. This is why there are hate crimes, murders, rape, speeding, unsafe lane changes (no turn signal), etc. Because while I might believe that doing 10mph over the speed limit is
not that bad, others believe it is morally repulsive to drive any faster than 5mph under the speed limit (trust me, they're out there...mostly on Sundays, it would appear).