You are presupposing that for some reason Facebook must do this. If they can not moderate then their service is defective. The fact that they want to make huge gobs of money does not “force” them to offer a defective service, they can just not offer it.
If a construction company said: “The only projects we can make a profit on are skyscrapers, but we do not know how to make a skyscraper without having it fall down and kill everybody in it.” They are not allowed to build skyscrapers no matter how important it is to their bottom line.
If a construction company said: “The only projects we can make a profit on are skyscrapers, but we do not know how to make a skyscraper without having it fall down and kill everybody in it.” They are not allowed to build skyscrapers no matter how important it is to their bottom line.