Because supposedly America is a developed nation. You are talking about anarchy and things out of fictional tales.

Right, Australia still has problems, but what they don't have is a gun problem and that is the issue at hand in this discussion.
Do you really think that arming everyone to the teeth would create a peaceful and working society? DO you think you'd feel safe walking around at night knowing everyone is packing weapons in their pants. Do you think that countries where citizens don't own weapons are living in a police state?