The issue is, however, the largest superpower is backing and supporting the actions of Israel in this regard. "The World" would have to label the United States as an active participant and begin the process of sanctioning and isolating the US. Either way, it wasn't morals or ethics that ultimately led to turning on Nazi Germany. Before the bombing of Pearl Harbor, the United States was very comfortable in keeping itself out of the conflict. At the time, Anti-Semitism was the soup du jour of domestic policy in Europe and America.

The Franks (of Anne Frank fame) attempted to immigrate into the US leading up to World War II, and despite Otto Frank's connections within the American government, and his connections as a businessman, him and his family were deemed a "security risk" and denied entry. They were one family out of thousands who were turned away by FDR's State Department. It was clear early on that the Third Reich was facilitating mass oppression against their Jewish population. The problem, ultimately, is that the prevailing opinions about the Jewish people were shared within the western powers. From an American perspective, what the Third Reich was doing with its Nuremberg laws wasn't too far off from what America was doing with its Jim Crow laws, in fact, the Nuremberg Laws were heavily influenced by the Jim Crow laws of America. Meanwhile, European countries facilitated the emigration of Jews from their borders through the Third Reich's first solution, which was relocating the Jewish people to "Israel", of which they covered the majority of the costs to do so.

The United States didn't enter into the war until after the attack on Pearl Harbor, which was a form of blowback resulting from the British and American embargo on oil heading to the Japanese Empire. Up to that point, the states had been operating Lend-Lease programs for weapons and supplying the Allied powers with material support in an attempt to allow them to deal with the Axis threat. There were great material interests in pushing the Third Reich back, as they had expansionist ambitions, ones that would see them control land and resources that the Allied forces had ready access to. Ambitions of conquest in Africa and Asia, as well as a colonization scheme into Russia. It wasn't until April 1945 that the Dachau Concentration Camp was discovered and ultimately liberated. The idea that the Allied powers were fighting against the Third Reich on Moral and Ethical grounds rooted in the treatment of the Jews is very much a misunderstanding of the timeline of that war. The European front was effectively finished by May that same year.

So this idea that the world "can find it in themselves to have a single moral or ethic, and then act on it", as if that was what happened in World War II, is idealism, and a revisionist view of the events of that war. I do not see this conflict playing out as the way you imagine it.