I don’t see how it would ever make sense to hold social media liable for user posted defamation.
Look at the recent Afroman defamation lawsuit and consider how YouTube is supposed to know whether that music video was defamatory or not. It took a court 3 years to reach a conclusion but you want YouTube to make that same call instantly, on millions of posts a day. What you’d get is a world where Afroman’s (non defamatory) speech basically cannot be shared on social media at all.
Look at the recent Afroman defamation lawsuit and consider how YouTube is supposed to know whether that music video was defamatory or not. It took a court 3 years to reach a conclusion but you want YouTube to make that same call instantly, on millions of posts a day. What you’d get is a world where Afroman’s (non defamatory) speech basically cannot be shared on social media at all.