Hitler's disdain for Jews had it's origins in the middle ages when similar anti-semitism was very popular. Jews disproportionately became bankers during that time as they didn't have the same usury restrictions as Christians. Christians joined the banking business later on with the Knights Templar, the Medicis, etc. later but Jews had quite the head start. So European and Hitler's hatred of Jews as disproportionately powerful and bankers stems from far before WWI and the Weimar Republic.