The Talmud is man made. God gave the Jews the Torah, or the law, but they wrote their own Talmudic laws to try to interpret what God said. They couldn't just take the Torah for what it says, they had to 'improve' on it. There are lots of Jews who follow only the Torah and the saved Jews are among them. They're still true Jews but fulfilled with the salvation of Christ.
They stop being Jews when they accept Christ, because tied up in being Jewish is the rejection of Christ. They remain, only, of Jewish ancestry. That's not the same as "being a Jew."
Another case of your personal bias changing your theology... ie a little isogesis vs exogesis. Hint; the Pharisees were masters at this.
Rejection of the Messiah was the error of the Nation of Israel & Judaism during Christ’s life & following His resurrection. Jesus Himself was the only perfect follower of Judiaism. Their error doesn’t magically define the religion they professed (which, practiced perfectly, gave Christ the righteousness He now imputes to His people) any more than identity politics practiced by one claiming to be Conservative taints Conservatism. Double hint.
An ethnic Jew who becomes a Christian is a Jewish Christian just like an ethnic Jew who is an atheist (as the majority are) is a Jewish Atheist. It’s common sense.
Contorting linguistics to suit a preconceived notion eroded ones credibility and ought to point a person toward the erroneousness of his views.
Luther’s vehemence, when read in context, was rooted in a deep and abiding care for the salvation of the Jewish people not condemnation of them for Jesus’ death as is so often put forth. He believed, as I do, that ALL have sinned and fallen short of the glory of God; no one seeks God we have all gone our own way.
This is another huge problem with the identity politics; it creates an us vs them when all there is is us.
