If you read the various exremist websites daily, you too will become paranoid simply because you're exposed to the rantings and ravings of lunatics daily.
Of course it is possible that one thing could set of a chain of events that causes a collapse.
But even day to day stuff can have a profound, if not societal, impact. I should have a 3 month supply of food, but not just because there might be a tornado or week long blizzard. When I lose my job or get severely injured I would also need it.
Guns are tools, and if it makes someone feel safer to have one, then why shouldn't they have one? Because one mentally ill person shot up a school full of kids? That's why no one should buy a gun? Talk about paranoia!