Why did the Jews get killed in the Holocaust?
After World War I, Germany was in an economic crisis and Hitler was looking for a way to gather people together, to rally them for an effort to dominate the world. The best way he saw that he could do this, is creating a common enemy that his people could learn to hate and attack.
Many of Hitler's compatriots held the view that Germany had not been defeated on the battlefield in WW1 but had been brought down by liberal, socialist and Communist subversives on the home front. In other words it was claimed that 'the Jews had caused Germany's defeat in World War 1'. Potentially, this made antisemitism explosive in Germany. Also, many people thought that the Jews were communists. In many hard-line right wing circles there was talk about a supposed 'Judeo-Bolshevist conspiracy'.