That's actually quite a theme in the Torah, and the prophets. Wandering in the desert for 40 years, and the Babylonian Exile were because of not trusting or of disobeying G-d. Presumably the Diaspora was God's will too (the argument that Judaism doesn't need a land was common enough) * but I'd not heard the modern application to the Holocaust. Why it would lead to support for Palestinians is worth asking.
* It's part of the wide definition of antisemitism (the IHRA "examples") to say it's antisemitic to question the loyalty of Jews to the country they live in. "Accusing Jewish citizens of being more loyal to Israel, or to the alleged priorities of Jews worldwide, than to the interests of their own nations."
The problematic "example" at the moment would be "Holding Jews collectively responsible for actions of the state of Israel" when collective punishment of Palestinians for the actions of Hamas seems OK.
First I don't hold the current young generation of Palestinians responsible, it is dire and we somehow need to get out of this vicious cycle.
However I would strongly dispute your analogy here around collective responsibility.
British Jews do not have a right to vote in the Israeli elections (in general of course) and therefore cannot be held to account for the current government or previous governments. Fine, in general most will take a side but that's very different from being accountable. It is clear that a significant number of people do take the view that Jews are collectively responsible. Whilst I applaud the generally peaceful protests in cities in the UK today, sadly I feel pro Israel demonstrations would be met with aggression, we are seeing a sharp rise in anti semitism which is unjustified, much of which stems from outright anti semitism or this view of collective responsibility of a religion.
Palestinians in Gaza have democratically voted in a Hamas government. Now you can turn around and say that they had no choice, it was under duress but that itself can be disputed. Arguments of Hamas the terrorists being such a small insignificant minority cannot be given if the same arguments of duress are used for nearly 2 million people. Equally when opinion polls are taken in Gaza where over 50% of people are generally positive towards Hamas then these arguments we see start to become weaker when we are talking about duress in a democratic election.
Even if you accept that it was duress, which I personally don't, it has only been 1 or 2 generations ago where they could have done something about it but they didn't, they, the arab states around and others, let it get out of control. It was only 2 or 3 generations ago that the same families of Palestinians rejected a two state solution with the option of Jerusalem being an international city, as did the Arab countries around it.
If you don't deal with extremism in your ranks early on, or you accept the serious negatives for some positives, when it gets out of control, then you have to share some of that accountability for the generations to come.
That does not mean innocents deserve to die, certainly not, but in terms of collective responsibility of a religion, I disagree with the point and analogy.