This.
IMHO, it isn't currently nor was it ever illegal to simply shout "fire" in a crowded theater. The 1st Amendment protects the word "fire" and associated phrases because banning it's use in public under all circumstances might in fact cause harm. If such speech was illegal, if I happened to be in a public place and saw the building on fire, the law would forbid me from warning everyone else. However using the Brandenburg v. Ohio SCOTUS decision, falsely shouting "fire" would be illegal if and only if, it "is directed to inciting or producing imminent lawless action and is likely to incite or produce such action." So your speech must be intended to likely provoke riotous actions in the very near future for it to be unprotected.
If you look at carry laws in the same light, carrying a firearm should be protected by doing what a law abiding citizen does on a daily basis i.e. not committing lawless action. We have a process we need to go through in New Jersey if we want to legally obtain a firearm. Once we meet those requirements we can keep purchased firearms in our homes. The state says they don't have a problem with this and apparently we are responsible enough with firearms when under our own rooves. But step outside with that legal firearm and our state says that simple possession indicates that an individual has the intent to incite, or produce as a byproduct, imminent lawless action. Inside you are a protector, outside you are a ticking time bomb. Further, NJ says a concealed firearm is not a legal means of self defense in public unless they deem you worthy of such protection. By showing a "justifiable need" and receiving a paper with your name on it, suddenly your unstoppable need to commit homicidal/unlawful acts disappear and you can be trusted to carry a gun.
Preaching to the choir I know, but just goes to show you how ridiculous our legal system can be.