Gun-Control

If politicians believed that "gun-control" reduced violence, why wouldn't they disarm the military & police?  Would the reason be because disarmament may only have the desired outcomes of peace, if all persons/"nations" agreed? But if those parties already agreed on peace, then why was the disarmament component a necessary step?

  If disarmament is the goal, why is armament required to enforce the disarmament? How does using force/violence of a minority group of armed-persons, to disarm the majority of persons, help to reduce the violence? Would not "gun-control" as it is typically advocated, potentially increase power-disparities, between those minorities of persons who either enforce the disarmament or those who ignore the disarmament-rules, and the majority of persons who are forcibly disarmed?  Would not that power-disparity, increase the potential profit of the armed groups to victimize/abuse/oppress the unarmed groups, and thus increase the potential for violence?

How many people have been killed by "private" murderers in the last century?
How many people were killed by dictators such as Pol Pot, or Stalin or agents of other political leaders in the last century?

If the purpose of "gun-control" is to reduce violence, and if political-states have killed more people than "private" murderers, then why wouldn't the object/goal of violence-reduction be to disarm governments/nations/political-agents?