Actually, replace with 'google'. Facebook did say they would permit political advertising without fact checking. Whereas google said they would enforce factualness
Facebook will let you broadcast lies in secret (ie targeted at specific small groups so you and I don't know what lies are being told) just so long as you pay facebook to propagate those lies. Nazi party propaganda targeted at those showing mental health problems, sure, just pay facebook and they'll do that for you. They've said so.
I really think this is the right way to think about what facebook are and what they do.