Strap these organizations down and cut them the fuck open with no regard for their wellbeing. If the procedure kills them, then so be it.
There is a threshold past which live dissection (https://en.wikipedia.org/wiki/Stasi#Recovery_of_the_Stasi_fi...) is the only way that trust can be restored. I assert we have run across that threshold. And before anyone whines about it; no, we are not as bad as the Stasi yet. The Stasi do not represent the position of the threshold, they were miles past it.
Going after Facebook would probably be unnecessary after we were through with the accused government organizations. At that point Facebook's innocence would either be clear, or it would be clear that Facebook was a victim in this. If we found reason to believe both of these were not true, then we could pursue them as well.
Honestly though - I don't know. It's why I asked.
Possibly they can't, because how do you prove you're not lying other than saying you're not lying? It's not like there's some sort of an unshakable, absolute truth hardware log that details every single data access.
There is something called "evidence" used exctly at those circunstances.
Of course, I have no idea what kind of evidence those companies or the US government have, they are not telling anybody. And that is evidence that they are lying.