Facebook has a right to free speech. They can moderate and curate content on their site.
Their commitment to your free speech is "free as in beer" -- as in, you're giving them content and they don't pay you a dime for it.
Their commitment to your free speech is "free as in beer" -- as in, you're giving them content and they don't pay you a dime for it.
What they do not have a right to is the claim that they should be treated as neutral carriers (like TelCos) when they in fact constantly exercise editorial control for the placement each item.
(If they merely posted a chronological list, they would have a valid claim for free speech and no exercised control)