Not that simple
There is a reason why we don't have the death penalty for every crime.
That reason is, it effectively backs the rat into the corner and they have
nothing left to lose, so they kill even more people.
Also, people with the authority to have weapons can decide to commit
crimes with them. Look at the situation at Fort Hood when a Muslim
major decided to start shooting unarmed soldiers. He claimed to be
doing it in the name of his religion, so it IS relevant.
Countries that want to control their people first take away as much
power as they can from them. One of the reason why the "Arab spring"
did not fully hit in Iran is that the regular citizen do not have access to
weapons. The reason why the Afghan central government has never
been able to take over its people (most who don't want it to exist) is
that they happen to be armed and are quite willing to kill those who
attempt to disarm them. And, since they ones that are sent to do the
disarming know this, it is rarely attempted.
