In fairness to Luther, he was reading the Rabbinical writings, which are viciously anti-Christian and contain all the negative stereotypes Jews are accused of, such as a dual morality system where it’s okay to fleece gentiles.
And since there were no Jewish writings against chrstianity before chrstianity existed to write against, I suppose you think that means that this represents some sort of deviation from Biblical Judaism.
You know, I don't think there were any Catholic writings against Protestantism or Protestant writings against mormonism before those religions existed. I guess that Catholicism and Protestantism are "apostate" because they didn't recognize the "new covenant???"
And his antisemitism came later in life and is not celebrated or condoned by the confessional Lutheran church. It likely also grew out of the replacement theology taught by the Roman church.