Rubbish is what you just said. You would have to prove that someone had intentionally lied and not just been mistaken which people often are. So your idea of prosecuting mistakes is rubbish. You see you can't win regulating people's freedom of speech.
I'm often amazed at how very little some people understand about what they say. And especially when it comes to "freedom of speech." Conservatives especially (this is my opinion only) seen particularly susceptible to really getting it wrong.
Let me offer up a hypothetical (so the Mods don't nail me): Am I free to say, because "to say" is just speech, that Beau Biden didn't die of brain cancer, his father actually murdered him -- and more than that, that I have certain "proofs" that I can't reveal?
Would I be free to declare that (through devious means) I've discovered the identity of
@74x12, and that he defrauded his last company of over a million dollars and should never be hired again?
Or, if I said such things -- things that have the raw power to severely damage the lives of real people -- should I not be required to prove my contentions, and if I cannot, to either retract them or suffer the consequences of doing real and permanent social, moral, financial or other damage to innocent people?
No, I think I'm learning something about many so-called "conservatives" these days: they like the rules, they like "law and order" so long as it delivers what they want, and will tear it all to shreds when it doesn't.
Welcome to fascism. That's how it starts.