The thousands of extra-legal killings that were the direct result of the election of Duterte as president (who was AFAIK elected with direct help from Cambridge Analytica and a vile social media campaign on Facebook) is also nothing to scoff at.

But I think the Rohingya genocide is way more insideous, because Facebook knew that their platform was being used for direct encitement of violence and coordination of progroms and chose to ignore it because they thought Myanmar would be a lucrative market and wanted to consolidate their monopoly power there.