We know how many Fediverse servers there are and how many users, it averages out at about 1 server per 1000 users. That's an average of at least 1 moderator per 1000 Fedi users.
To match this ratio. Facebook would need 3 million moderators. I doubt they have the capacity to pay that many people, their entire staff is about 80,000. FB may run moderation sweatshops, but I doubt they have 3 million people in them, and if they do then the working conditions/pay must be immoral.