Well, the difference is still there. You can switch to a different social network without too much difficulty (you miss out on that platform, but that's as far as the cost goes); You can't just declare yourself as part of a different country without actually up and moving there, changing your job, getting the new place, and rebuilding most of your connections, and potentially learn a new language depending on where you move.

Except that people can just leave facebook and go use something else if they don't like it.

Don't get me wrong, I am deeply disturbed by the level on control facebook (and google) exhibit over news, information, the internet. But it's a fundamentally different thing then the government doing it.

I remember one of the wiki leaks releases from last year implied that google/Facebook had the capability to shift political opinion by selecting what people are exposed to.

When the government does this I think it's actually less harmful because people are aware the government wants to manipulate opinion.

The capability to individually tailor propaganda like is already done with advertising is much worse I think.