That's hardly the worst case scenario when there are countless stories like "Facebook Allowed Advertisers to Target Users Interested in “White Genocide” — Even in Wake of Pittsburgh Massacre"[1].
There's also the time Facebook's targeted ads were used to facilitate genocide in Myanmar[2][3].
[1] https://theintercept.com/2018/11/02/facebook-ads-white-supre...
[2] https://www.globalwitness.org/en/campaigns/digital-threats/r...
[3] https://www.amnesty.org/en/latest/news/2022/09/myanmar-faceb...