Brandolini's Law

Any information asymmetry will produce incentives to exploit Brandolini’s law. If you pay attention, you will begin to notice frequent examples.

It's not legal to yell "Fire!" in a crowded theater. Why is it legal to yell "Hydroxychloroquine cures COVID" on the crowded internet? Is it the immediacy of the harm? Maybe it's not necessarily legal, just untested in court?