If they use an algorithm to promote posts to increase their bottom-line instead of some neutral and transparent way (such as reverse-chronological feed of what

If they use an algorithm to promote posts to increase their bottom-line instead of some neutral and transparent way (such as reverse-chronological feed of what people explicitly followed) they effectively act as an editor and should lose whatever Section 230-equivalent protection they are currently using. Facebook (and other "growth & engagement" platforms) currently want to have their cake and eat it too. They act as an editor, selectively promoting certain content that increases engagement and thus their bottom-line while not taking any of the liability. Newspapers can do this too (and to a certain extent, do) but are under strict regulation which limits the damage (yes, tabloids are a thing, but none of them would publish outright calls to violence and promote illegal activities, something very commonplace on Facebook because outrageous content generates more engagement).