.. When everyone has a gun, there is no violence.
Sorry, but this is just rubbish.
No, when everyone has a gun, there is LESS violence, and any violence that does occur is usually quickly contained.
Right, I completely agree that there is less. I don't agree that there is "none."
For the record, statistics have already proven this as well. If you look at the number of crimes with guns that are committed in various businesses, you will find that statistically they happen MUCH more often in places where weapons are banned (counties) than elsewhere. This isn't a coincidence; people want to commit crimes they can get away with. If everyone is capable of stopping them, their chances of success go down and therefore the number of people willing to take the risk does as well.
You'll always have those that are "insane" and will commit crimes regardless, though.