Four thousand years ago Moses, with the Ten Commandments, laid the foundations for our civilization: "Thou shall not kill.... Thou shall not steal.... Honor thy Father and thy Mother...." Two thousand years later Christ expanded those ideas: "Don't do unto others.... Love Thy neighbor like thyself..." It took another two thousand years for the Judeo- Christian civilization to develop and mature. The Holocaust with its unbelievable cruelty, was a litmus test of this civilization, and it indicates its failure.
It is true that Hitler and Nazism bear the major responsibility for this tragedy, but Hitter could not have achieved his goal without the active help of the host nations and tacit help from the whole world. The European Jewry was not concentrated in a single location but scattered among host nations like Poland, Ukraine, Hungary, and Rumania. The Jews spoke the local languages and were not easily identified. The Germans needed the help of the local population in identifying the Jews, isolating them in ghettos, starving them to death, catching the escapees, conducting the moping up operation etc. And help did they receive.
In the Ukraine and Belarus, peasants, caught Jews in the forest, bounded them like pigs and delivered to the Gestapo in exchange for 2 liters of vodka. In Romania Jews were slaughtered like animals in slaughterhouses. In Hungary, the "Blue Donau" turned red from the blood of Jewish children killed by the Hungarian Fascists. Slovakia paid the Germans for each Jew taken to Auschwitz. In Poland Jews that escaped from Treblinka Death Camp were killed in the forest. In Poland Jews were killed mercilessly even after the war.
It is true that a small fraction of the population denounced or killed the Jews, but it was the indifference and the hostile attitude of the majority toward the Jews and the silence of the political religious leadership made the cooperation possible. The actions and attitudes of the majority can't not be reconciled with the teaching of Christ, or the Ten Commandments.
Another condition necessary for the Hitler's success was secrecy. The secrecy was necessary for keeping the victims unaware of their impending doom and keeping the German population unaware of the mindless killings. The Holocaust happened in silent and void world.. No voices of protest were heard, no rescue efforts were made. Many bystander nations eagerly participated in plundering the Jewish properties; the Swiss closed the border to Jewish refugees but eagerly accepted the gold extracted from the mouths of Jewish victims. The State Department and the English Government tried to conceal the atrocities.
The Allied leadership was afraid to convert the WWII into a war to save the Jews, afraid of being flooded with Jewish refugees, made no effort to stop the slaughter. In countries like Denmark, or France, where the Churches raised their voices in defense of their Jewish compatriots, the people, responded and saved Jews. It is safe to assume that similar actions in other countries could have a million of Jews. The devastating effect of the Holocaust is a is a powerful confirmation of the failure of an indifferent civilization.