If you do not partake in a war when a war is waged against you, you lose, and you either get subdued, or perish altogether. This is why pacifism for some part of a society is only possible when another part of the society is willing and capable of using lethal force to defend the society as a whole.
Due to this, it's important to always have sufficient quantities of very efficient weapons, exactly so that you would never have to put them to use.
War has existed as long as humans have. If you have any ideas for how to remove fear, aggression and disagreement from humans you might just be a god or a saint.
