The submission on the Greek genocide committed by the Ottoman Empire in 1914-1922 that claimed 450k-750k lives [1,2] was placed ~34th on HN (7 votes in ~40 minutes). About ten minutes later it was gone, and couldn't be found among the first 300 submissions, despite the story not being flagged.
Since discussion of the 1921 Tulsa race riot that took place at the same time seems to have been allowed [3], I assumed this story was also within the rules. Is this not the case?
[1] https://news.ycombinator.com/item?id=24600458
[2] https://en.wikipedia.org/wiki/Greek_genocide
[3] https://news.ycombinator.com/item?id=22221180