This is wrong, even in the United States. There are rare circumstances where a company's property is open to the public to such an extent that they become subject to first amendment restrictions (e.g. Marsh v. Alabama). Some states, such as California, have even greater restrictions on private parties in their state constitution. CA's constitutional speech protections prevent shopping malls from expelling petitioners from their premises, even if the mall disagrees with the speech.
Extending this body of law to, say, Facebook would have problems, of course. But I don't think it's so clear that all sensible adults know that censorship is only something the government does, and are happy letting any corporate behavior, no matter how extreme, pass without scrutiny.
Extending this body of law to, say, Facebook would have problems, of course. But I don't think it's so clear that all sensible adults know that censorship is only something the government does, and are happy letting any corporate behavior, no matter how extreme, pass without scrutiny.