Well, something to consider: during the time that the US Constitution was being written, the most common site to exchange information (usually pamphlets) was the local tavern or coffee house. Sure, if the proprietor was being a prick you could always bring your friends to the shop across the street. But that environment influenced the founders' ideas about how information is exchanged and debated, and it's the format the law of the land was written for.
Facebook is a global coffee house. Everyone can be there at the same time. But that also means it is very hard to use an alternative, especially as Facebook buys relevant competitors of information exchange like Instagram and WhatsApp.
Suddenly, we are in a situation where more people can connect than ever before, but for the vast majority of people, because of convenience and the lack of tenable other options, there is hardly any other choice. Other social networks that simply tried to clone Facebook never got off the ground because everyone was already on Facebook. I would truly love to close my account and leave but it's hard to stay in touch with friends from outside the United States, especially if Instagram and WhatsApp are out of the question.
Given Facebook's overwhelming presence in modern daily life, it is necessary to regulate what it can or cannot do for the benefit of the common citizens. The degree of regulation will always be debated, and rightly so, but to pretend that a private entity of immense social might is free to do as it pleases is to willingly give away power and authority from the state, and in a democracy, from the people themselves.
EDIT: wow, downvoted to hell for this one. It would be so fascinating if just one person could describe what makes my view so wrong.