You are just naive. I was pretty naive until I was robbed lol.
How am I naive? How much were robbed and was it while you were walking around away from your car/home? Yeah you are less likely to get robbed if you carry a gun around, but you are also more likely to die from a robbery if you carry a gun around also. You obviously weren't killed when you were robbed while you might have been if you had pulled a gun out. Pulling a gun out might scare a robber or it might turn a simple robbery into a life/death situation.