That's a very common misunderstanding (even among Americans) of what the First Amendment actually guarantees: It protects you from government censorship of speech, but does absolutely nothing to compel private individuals or corporations to carry your speech. (In fact, compelled speech has been ruled to be a violation itself.)

That absence of such legal protections can definitely be seen as having a chilling effect on free speech in practice, but as I interpret it, currently the assumption seems to be that legal intervention is not necessary due to market forces achieving the same or a similar outcome implicitly. There's also strong resistance from a value perspective against the idea, since these provisions themselves might be incompatible with the FA for reasons mentioned above.

You can definitely have some discussions around whether additional "duty to contract" rules should apply, e.g. in the same way as there's a law in Europe that makes it illegal for banks to not give somebody a bank account in certain circumstances, but nothing like this exists at the moment.

> Right now, it is the ONLY wide audience platform in the world, where Russian people can freely (as opposed to, say, HN) write what they really think

Hackernews has always been very strictly moderated to maintain a specific type and culture of discussion. By necessity, that excludes certain types of comments. In that sense, it's always been very far away from a "free speech platform".