I suspect social media companies don't like the message because they don't like the costs required for good moderation. They don't really care about free speech, that's just spin.
I'd like to call Occam's Razor, but, then, when has it become that the most selfish interpretation of an organization's motivations is the simplest one? Maybe it's simple simply because it aligns with my beliefs. Something to ponder.
"Freedom of speech" is the new mantra you have to repeat if you want Americans to stop thinking about a problem.
But yeah, would agree that "freedom of speech" wasn't a design pillar or anything for FB.
This is as true as saying "more code = more programming" -- possibly a technically correct statement, but if your goal is to create something valuable (to your business, to society) this won't help.