I'm assuming here that Nazi Germany, like most of Europe during the '40s and now, was a Christian nation. I'm actually watching Schindler's List right now, and the church scene got me thinking. How did the Nazi regime reconcile the actions of the Holocaust, the brutal treatment of the Jews, homosexuals, Romanian gypsies, etc., with Jesus Christ's teachings to love each other as yourself, etc?
In 1933, just over two thirds of Germans identified as Protestant. Early on, the Nazis tried to work a bit with the churches in Germany. The German Christian movement was one of the results of this. The German Christians were a Protestant sub-sect that aligned themselves with the National Socialist ideology. One of the primary arguments used to support their antisemitic views was that Jesus was betrayed by the Jews. Using this, they tied it in with the "stab-in-the-back" myth that was propagated after the First World War and essentially said that Germany was betrayed from within.
Another important factor is the history of Protestantism. Martin Luther, the main player in the Protestant Reformation, notably became more antisemitic later in life. Early on, he had hoped to convert Jews to Christianity by being kind to them, he despised how the Catholic Church had treated them. After years of little success, he began attacking Jews and wrote a treatise entitled: "On the Jews and Their Lies." The Nazis used Luther's writings as supporting evidence that Jews were evil. Importantly, the Nazis were seen as some Protestants as a sign of a new reformation. They believed the Nazis would return Germany back to its proper status as it was before the First World War. They saw Germany itself as a nation chosen by God.
Ultimately, a lot of the reconciling between the Holocaust and the antisemitic policies were done on a local level. Around 1/6 Protestant clergy were German Christians and they propagated antisemitism. Even in groups such as the Confessing Church, another Protestant sub-sect which found itself at odds with the German Christians over the issue of state intervention in Church affairs, they were not entirely against the Nazis themselves and some of them held antisemitic beliefs. The Nazis ended mostly ignoring the churches after a few years, both the Protestant and the Catholic churches. Due to this, there were many within the German Christians who wanted to regain Hitler's favour which led to even more antisemitic fervor.
The Nazis used a sort of a consequential argument for dealing with the Jews. Getting rid of them would be a morally challenging task but in the end, once the Jews were eradicated, the world would be more ethical and therefore killing Jews was argued to be an ethical action. Some of the Protestant clergy helped give solace to those who struggled with the idea and told them that what they were doing was ethical.
Essentially, what it comes down to is that there were many vocal National Socialists within the clergy who propagated the Nazis views and argued that antisemitism was ethical.
Sources used:
Baranowski, Shelley. The Confessing Church, Conservative Elites, and the Nazi State.
Burleigh, Michael. Sacred Causes: The Clash of Religion and Politics, From the Great War to the War on Terror.
Dietrich, Donald, ed. Christian Responses to the Holocaust: Moral and Ethical Issues.
Erickson, Robert, and Susannah Heschel, ed. German Churches and the Holocaust Betrayal.
Gerlach, Wolfgang. And the Witnesses Were Silent: The Confessing Church and the Persecution of the Jews. Translated by Victoria Barnett.