The police and military are not authorized to intentionally kill innocent human beings. When innocent human beings are killed, their deaths are either unintentional, unavoidable, or they are caused by the misjudgment, negligence, or criminal behavior of individuals or their leadership. You are correct on one point, however: killing in self-defense is absolutely justified. But remember, if you have to kill in self-defense, the person who died was clearly not innocent.
Now let’s compare these cases to human abortion. A little unborn boy or girl is not a combatant, not a criminal, and not attempting to harm anyone. They are simply doing exactly what they must do: grow bigger and pass through the next stage of life. Trying to justify the killing of defenseless children while they are cradled within their mother’s womb because others kill outside of the womb is, and I’m being kind – pathetic.