He learned his anti-semitism when he was a RCC Priest.
shalom b'SHEM Yah'shua HaMashiach
Luther was actually somewhat philosemitic when the reformation began but turned viciously anti-jew in his later years. On the Jews and their lies was written only 3 years before his death.
Luthers anti-jew writings were often quoted by the Nazi's during their rise to power....from wiki:
....the Nazis displayed On the Jews and Their Lies during Nuremberg rallies, and the city of Nuremberg presented a first edition to Julius Streicher, editor of the Nazi newspaper Der Stürmer, the newspaper describing it as the most radically antisemitic tract ever published.
Luthers protestant church was deaply anti-jew and played a role in the run-up to the holocaust. It is documented fact.