OMG, CONSPIRACY!
That, or all the misinformation that was spreading like you posted lead to Facebook instituting a bunch of policies to combat it, which is what Trumps post (and a bunch of others) contravened. That happened in July, which is in between those dates you mentioned.
It's as if people don't need to make up rules until they need to!
No mention of WHO/China misinformation though, eh? Must be nice to be able to pick and choose which misinformation gets spread on your [strike]platform[/strike] publisher and which gets censored/blocked/banned. Almost like it's political or something.