How would fact checkers access the 90% of private content? And should they? I don't think so, even if the respective private content is questionable.
The EU goes its own way with trusted flaggers, which is more or less the least sensible option. It won't take long until bounds are overstepped and legal content gets flagged. Perhaps it already happened. This is not a solution to even an ill-defined problem.
Good. Private communication is private, even if it's a group. The nice thing about the crazy is that they're incapable of keeping quiet: they will inevitably out themselves.
In the meantime, maybe now I can discuss private matters of my diagnosis without catching random warnings, bans, or worse.
What kind of diagnosis spawns so many fact checks that it's a problem? I'd think any discussion about medical issues would benefit greatly from the calling out of misinformation.
If you assume they are immune to politics (not true but let's go with it), this is the most obvious reason.
They've seen X hasn't taken that much heat for Community Notes and they're like "wow we can cut a line item".
The real problem is, Facebook is not X. 90% of the content on Facebook is not public.
You can't Fact Check or Community Note the private groups sharing blatantly false content, until it spills out via a re-share.
So Facebook will remain a breeding ground of conspiracy, pushed there by the echo chamber and Nazi-bar effects.