Controversial content breeds engagement, which is, I would say, one of the most important metrics companies like Meta, Google, or Twitter (sorry, X) rely on.
X would allow a literal nazi posting freely on their site, with the occasional post deletion, as long as it generates impressions. They could remove the content, they choose not to.
https://www.techdirt.com/2019/11/20/masnicks-impossibility-t...
Problem with social media is they try hard to create false/non communities at scale to sell to advertisers. The social part is just pure manipulation to get people to look at ads. True social is problematic for them so they suppress it.