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
I don't think this is shadowbanning. I have another definition of shadowbanning.
A post with a few flags get a small penalty, and with more flags it gets a [flagged] label and more penalty, and with even more flags it is autokilled. Perhaps the post got only a few flags? Perhaps you are overestimating the normal decay?
About the Tulsa riot, this site has a lot of users from USA (60%?), so it has a USA bias. [Hi from Argentina!] Post related to other countries sometimes get ignored.
Also, there is a bias for current events, and things related to current events. If tomorrow Turkey decides to bomb Athens, my guess is a repost would get more traction. (But I hope we can never test my hypothesis.)
Front page average votes as I count them now is several multiples above 7 votes