Facebook would be so much better with fact-checking. It seriously would improve the state of the world.
What happens when their moderation team decides some anti-vax nuttery is "a fact" and then bans anyone disagreeing?
As a reminder, this is a group that handed out punishments for pictures of infants being breastfed.
Is the world better off without that opinion (or fact, depending on who you ask?)
You see how this can be sticky.