I agree on what you say about people doesn't choose to be violent, well at least not the overwhelming majority!
But religion is something that is also called faith, its hard wired into you since the day you were born, it has a big part in people's deeds, when you allow that bit.. license to kill from the faith.. people will misuse it..
There's violent people from all walks of life... belong to all religions.. in Islam though you can justify it through the holy book.. In Buddhism you cannot... A BIG DIFFERENCE!
Bein muslim is to have rational faith ! Islam tells us to ponder on the authenticity of the the religion you are following and not blindly follow ! It is a choice of submission not the predominant brainwashing or cultural sprouts you see !
Even if religion does not address the issue of killing, people will still kill and will have all sorts of licenses for that ! Eg racial (superiority of aryan race) political even for honor !
This is precisely why Islam address the issue in detail and provides stern conditions in which muslims can use force. For eg when they are oppressed , in self defence and like mentioned above there are rules of combat ! Eg no killing of women and children or civilians , only combatants , you are not even allowed to strike in teh face or even a cut a tree in enemy territory and if the enemy declares peace you are supposed ' to escort him to a place of safety' ! There are conditions to engage in combat and consequence for unjust actions ! Although people will try to justify everything , if ponder logically you can clearly see the contradiction in teachings and practice unless there is already a preinstilled bias against religion !
You see what your saying is in Budhism since the issue is not there , you are not accountable. Like for example if a man tries to kill you and you kill him instead , robbed him and mutilated him can you not say 'well its not addressed so im safe' . Wht if some one wages war on you ? Similiar with evolutionary atheist philosphy.Survival of the fittest , no guidlines , no accountabilty We beleive violence or use of force is allowed in certain . very prescribed circumstances !