This argument is frequently used, but is not really accurate.
I could indeed yell "Fire" in a crowded theater to my little heart's content, provided I was not somehow restrained, or until someone forced me to stop. I would certainly, and would expect to, be held accountable for the resulting pandemonium and any damages.
The only way I could be prevented from doing so would be to physically restrict my ability to do so, perhaps by gluing my lips shut.
But, what if there actually were a fire?
It is this prior restraint that the Statists want to enact upon lawful gun owners. They want to make sure that everyone cannot yell "fire", instead of holding folks accountable if they do so inappropriately.
GMTA.