I really have to differ with you. People who chose to carry weapons or are required to carry weapons, don’t just go out and buy a weapon without a clue how to use it, and then just start shooting randomly when faced with a threat. There is just no point in carrying a weapon if you don’t know how to use it, and no one would. An armed society is a polite society.
I think Heinlein’s idea was that it was frozen in fear, but I prefer to see it as that it is polite because it now understands where rudeness can go.