Good thing we came to terms with that in 1789.
You can't yell "Fire!" in a crowded public space as a prank nor can you yell "Bomb!" at an airport as a prank. We have determined that's NOT protected speech. Neither is slander nor libel.
You're going to have to work a little harder at convincing me why spreading misinformation that can kill people should be regarded as protected speech.
You're going to say Trust the Scientist, I will point you to the replicability crisis...
Maybe Zuckerberg should be an adult and recognize the power his platform has to misinform, and kill, people. So far, he appears to be content in keeping his head firmly planted up his posterior so long as he's making money. I define that as evil; others may disagree.