This is true, but likewise the entirety of Europe and much of Asia and the Middle East suffered to. Here in the UK, no-one commemorates the British civilian victims of German Bombings, as one tiny example. Likewise civilian victims of other 20th century wars.

WW2 was a western world international trauma with no-one unscathed, and various groups suffering to different unimaginable degrees.

But the Holocaust, in its extreme brutality and relentless focus on racial genocide by a civilised Western nation, was a different level altogether.