And though it in no way diminishes the evil of said infamy, I personally believe, as someone who considers himself a careful Bible student over many decades, that one way the Lord on High will one day bring good out of that most diabolical chapter in (in)human history...
...is by using it to shine a spotlight upon that equally infamous and diabolical chapter in human history, the Cross of Calvary (whereby an Individual as opposed to an entire people group, suffered horrendously at the hands of a merciless and unmerciful bloodthirsty mob)...
in this way (and I fully appreciate the thought/insight may well not be original, though I did indeed come to/arrive at it on my lonesome (with the Holy Spirit's guidance I have little doubt):
When in years to come - if that's how long the prophecy has to run - the Jewish nation is beseiged around and about by, according to Scripture, pretty well every nation upon earth, and perhaps two-thirds of their populace is wiped off the face of the earth (if that fairly common interpretation of prophecy is indeed correct), they will recall the treatment meted out to One of their own in the faraway distant past...
...and then everything will quite literally 'click' for them...
No, I'm in no way, shape or form seeking to find yet another sort of justification or rationale or excuse for those aforementioned horrors and barbarities and evil - God, as the Newer (and indeed Older) Testament scriptures make very clear, is not - indeed cannot be, consistently with His holy and loving character - ever 'the Author of evil'...
And yet, as Romans 8:28 makes abundantly clear, 'penned' by a man who in earlier times was a most relentless, brutal and bloodthirsty foe of the new sect of 'the Way' as it was then termed, God has a way of taking the most horrible things and making something beautiful out of them...
And thus and so the wonderful prophecy of the penultimate book in the Old Testament will yet come to fruition:
And it shall come to pass in that day, that I will seek to destroy all the nations that come against Jerusalem.
And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn.
In that day shall there be a great mourning in Jerusalem...
And the land shall mourn, every family apart...