Bringing a gun into the theatre and texting during the previews were both violations of theatre rules, not necessarily city/state/national law (not sure how the Fla CCW law is written so possessing the gun there could indeed have been illegal).
Either way, if you feel threatened enough over a bag of popcorn that you feel the need shoot someone, you are a miserable POS coward deserving of spending the remainder of your worthless life in prison and having your ass sued off in civil court.
I agree if you are talking about the shooter.
Personally I won’t start or escalate a confrontation if I am armed. I am not armed out of fear, I am armed for the same reason Sam Colt was armed.
To be equal.