When Pilate saw that he could not prevail at all, but rather that a tumult was rising, he took water and washed his hands and said, I am innocent of the blood of this Just person. You see to it. And all the people answered and said, His blood be upon us and on our children. (Matthew 27:2425)
Some would say that verse 27 (emboldened above) is indicative of when things began to turn bad for the Jews, i.e., they took upon the death of Jesus in a far too personal manner even going so far as to include their heirs and were forever cursed for it.
As that is not the way of the Christ who came to complete the Word, I seriously doubt it. People are people, which is to say they're assholes and more often than not toward one another. Hitler was not a follow of the Christ and like so many men before and since did what he did for his own desires. He was an even bigger asshole than Nero.
As for Dorian, that the Holocaust happened is fact. To deny fact is to deny the truth and in doing so make a fool of oneself. Nothing is unforgiveable. Remember to forgive is divine but to remember is all too human.