In real life, nobody murders over 1 million people and can pretend it canbe covered up, especially in one of Europe's biggest and oldest cities. And when the Germans do that shit, Germans won't have a civilization afterward. It's one thing to kill Slavs when you haven't done anything too unforgiveable, but when you do that to a major European city, the Germans ITTL will be lucky to see the Bronze Age by the 24th Century.
Your argument is still not convincing. Utterly fails to convince.
Perhaps up to 30 million Soviets died during the war. Is 1 million more really going to push the Allies over the edge? Considering the actual death camps, roaming einsatzgruppen, mass starvation, and anti-partisan operations that helped cause that 30 million Soviet dead (not to mention all the casualties of the war) didn't push the Allies (or the Soviets) into the kind of hysterical shock you're suggesting, even if the Nazis carry out their mass crime, it's not going to lead to the scenario you suggest.
1 million dead is nothing, when even the LOW ESTIMATES of Soviet dead already cover 2 million civilian dead from forced labor, 4 million civilian dead from famine, and another 7 million civilian dead from intentional violence. So if those figures become 2.5 million, 4.5 million, and 7.5 million? It's statistics at that point.
It's simply going to be yet another great crime - rumored, but not verified during the war - that will be punished afterwards. The massacre will be remembered as one of the Nazi's greater crimes, but it's not going to push the Allies into wiping out the German people.
