I've written a post or two about the 2nd amendment and the right of the people to keep and bear arms but it's not really guns that are at issue it's YOUR RIGHTS. And my rights. Guns are probably the most heated topic that deals with rights though and tends to be the lead argument.
Why shouldn't a person carry a gun? Give me a good reason. Say you sit down at the food court in the local mall and you see someone wearing a gun. Are you afraid? If so, of what? That he's suddenly going to stand up and start shooting everyone in sight? Sorry but that's not rational. Let's say that he just has a large knife that you can't see and homicidal tendancies. Are you safer now? Let's add to the scenario then.
Let's suppose that there are no guns in the world. Guns were never invented. The guy with the knife is 6'2" and muscular and you're a 5'5" woman. There's not a cop within reasonable distance. This guy stands up and pulls out the knife and advances towards you. Violence without a gun. But you're no less dead.
Guns and the willingness to use them are the defense against brute force rule. They are the equalizer. A gun in the hand of a willing citizen beats two cops investigating your murder.