Perhaps the question is: To what degree is the state entitled to keep secrets?
If anyone had a definitive answer to that, that was both consistent and prudent, they'd have the answer to the $10 million dollar question lol
The notion that "some secrets have to be kept from the people, because the people could expose it to our enemies" is prudent, but is not consistent within pure representative republic/democracy. (in that, we're paying for something, but not allowed to know the details of what we're paying for)
The notion of "if we're paying taxes for our military and homeland defense and intelligence agencies, we have a right to know what they're doing" is consistent, but not prudent, in that we all know some blabbermouth would post it on facebook and a North Korean or Russian sockpuppet account would love to get their hands on that information in ways that would make us less safe.
It's actually a dynamic I've pondered quite a bit and still don't have a great answer for.
On one hand, I understand why the government would want and need to keep secrets in the name of national security, you can't just let everyone and their brother know what our missile defense systems entail, that would last all of 10 minutes before it ended up on someone's social media feed.
On the other hand, a government that has the power to take our money and use it for covert stuff with no obligation to tell us, is a government powerful enough to do secret stuff against us as well. (see: NSA wiretapping and the Patriot Act)
It's a balancing act, and quite a tough one at that...
With regards to social media companies, I've long said that the moment they got called up to senate hearings and coerced into setting ToS provisions that favored what the "in-power" administration wanted and subsequently complied with the indirect demands, they became "State Actors" (and should be held to the stipulations in the State Action doctrine of the constitution). But that still leaves us struggling with the broader question you asked.