Just as many people call themselves Christian, without being born again, would you agree that many call themselves Jews, not by being one inwardly, but outwardly?
There is a racial Jew that born in the line of Abraham, Issac and Jacob.
These Paul calls 'my brethren, my kinsmen according to the flesh'(Rom.9:3)
A Jew today who receives Christ becomes a Christian is no longer considered a Jew, just as a Gentile is no longer considered a Gentile (1Cor.10:32, Gal.3:28).
A 'true' Jew would follow the path of their father's and believe in Christ (Jn.8:39-40).
Still, all of the racial Jews will one day believe on Him, when they see Him coming in glory (Heb.8:8, Zeck 12:10).