The irony of writing that question...

It seems like a perfectly cromulent question to me.

This is not mathematics, you can't expect a QED here.

Free speech is certainly pretty good against government-backed disinformation. Governments have a lot of power to push their POV anyway; add the ability to prosecute dissent to the mix and the system loses necessary feedback.

It gives me little shock every time I realise I have lived long enough to see the world turned upside down. What was once regarded as an anodyne statement of fact has become increasingly contested and is even rejected by a sizeable section of society. That is, that free speech is a universal right, and a good thing. For a very long time, going back to the 19th century, at least, every British (and American) politician, or other public figure, would have agreed with Voltaire's position on freedom of speech: "I disapprove of what you say, but I will defend to the death your right to say it". How times have changed.