Again, by all means, protest Google/Amazon/Facebook. I'd love to see the state of affairs change too. Just don't pretend like missing your church bulletin is equivalent to actual imprisonment.
Everybody understood implicitly that you only put in your own information. Giving away other people's personal information to a some company for which it is clearly valuable is not considered nice. It's simply not yours to give away. For the few who didn't understand this most companies had this in their terms of service anyway, as there could be legal risks involved.
All those companies are gone now. They are out-competed by a select few very large companies who did everything possible to make it very easy for people to input everyone else's contact information in their database, including making that behaviour default in the software that ships with your phone. In the beginning you could ask people nicely not to input all your personal info in third party phone book services. That's not really possible anymore.
The days when you could practically opt out of these companies are long gone.
Easier or more difficult to get by without shouldn't distract us from the core point GP made, that corporate (arbitrary) censorship, with no redress, should be taken as seriously as govt censorship. These days they are just two arms on the same chimera.
The answer is: groups of people (and corporations are groups of people) are free to limit speech according to whatever rules the group decides upon. What you're proposing is that certain large corporations be treated as quasi-governmental entities. Which is a _free-speech restriction_.
Not saying it's a bad idea, necessarily. But I'd rather my freedom to say that certain types of speech are unacceptable was guaranteed.
My point is censorship is a huge responsibility and power, especially when it is done at the scale govts and multi-national corps do, and therefore it needs serious transparency and checks and balances, in both cases.
I don't see this happening to satisfaction. Instances of regrettable censorship stay regrettable, and keep recurring.
I just can't quite go as far as to say that Google or Facebook should be treated as governmental entities. The bill of rights restricts what government can do. It has never been interpreted as restricting what an individual person can do, even if that person heads a giant corporation.
Solve these problems another way, not by literally nationalizing social media.
Because the "opt-out" process is orders of magnitude easier. You don't have to use Google. Microsoft has online document creation applications, as does Apple, assuming iWork still exists. Or you can just write documents offline using any of several thousand tools.
Corporate censorship is entirely under your control. You can always stop the censorship by simply not saying it using that corporation's tools. Corporations can control how you say something, but not what you say. Governments can control the act of saying it. One is far worse than the other.