Using algorithms to determine the order someone sees things in is, in my view, a social media company applying editorial content.
And therefore, if their editor (which is an algorithm for Facebook and Twitter) promotes something that’s slanderous or libelous, Facebook should be held to the same standards as an editor who could be prosecuted for that.
Same with someone who writes something on Facebook. Write something slanderous? You are like a newspaper reporter at this point. Facebook promotes it in the algorithm? Now their algorithm is responsible, too.
Facebook, nor its users, have any significant negative consequences for publishing anything that is false or misleading. Until that changes, I doubt the company’s behavior, nor individual posters, will change.