So when you write something at facebook you ask a company to host your story under their domain. And as the company is held responsible for what they host, they have to review everything before publishing it.
When we wrote forum posts back in the day, it was no different. If the forum operator didn't like what you wrote, he just deleted your post. So if you wanted to post something nobody wanted on his website you just made your own website.
And so it is today. Unless you want to periodically write hate posts you should be able to find a web hoster or ISP to share your opinion with the world. The only misconception is that because facebook is such a large 'forum', everybody thinks it cuts his right of free speech when facebook does not want to host his opinion.
Yes, I know that many people use facebook as their primary means of communication and that therefore their channel to the world is 'censored'. And Actually I have no simple solution to this problem, as my solution would involve to not use facebook in the first place.
So I think there is a difference between a moderated facebook 'forum' and a censored internet, which some countries have and which is a real danger to the freedom of speech.