This isnt true at all.That is not true at all. It is not normal for crazy guys to run around with guns. Yes there are a bunch of people like this across the span of the entire country (over 300 million people) but 999 out of 1000 people you interact with are not going to be running around with guns.
There are more guns owned by private citizens than there are private citizens. And concealed carry exists in a good number of states.
You may not always know the lunatic next to you has a gun, but theres a good chance they do.
This is why people started running when a man yelled "Heil Trump!" In a theater.