While judgment did come due to rejection of their Messiah and persecution of His own (Forbidding us to speak to the Gentiles that they might be saved, to fill up their sins alway: for the wrath is come upon them to the uttermost: 1 Thessalonians 2:16) yet one of the most reiteration teachings in Scripture is that "The fathers shall not be put to death for the children, neither shall the children be put to death for the fathers: every man shall be put to death for his own sin." (Deuteronomy 24:16; cf. 2Ki 14:5,6; 2Ch 25:4; Jer 31:29,30; Eze 18:20)
We all are effected by choices our forefathers made, for good or bad, but we are not punished for them. And it is the devil who wanted to exterminate the Jews and thus charge God with not keeping His promise, and Hitler was one of his proxy servants (as liberals are today). That said, I suspect that overall the Jewish culture in 1930's Europe was very insular and self-righteousness while being good at controlling wealth, and which did not endear themselves to the population, making it easier to make the Jews scapegoats for Germany's problems. But they need to receive the ultimate Scapegoat of Lv. 16.
When an individual Jew receives Christ, i.e., believes on the death, the burial and the resurrection (1 Corinthians 15:1-4), the cycle is broken. Those that reject Jesus Christ continue in the traditions that damn them in the first place. The Jews, as a nation, brought upon themselves a curse from God (lack of His blessings), but as individuals they have a choice to make.