I get it. Peace hasn't eradicated all use of deadly force, so peace has failed. "Cry havoc, and let slip the dogs of war!"
I'd rather die like a sheep than live in a world where everyone needs to be armed.
Real life, true situation. A family friend kept a licensed handgun in his cash register. He'd been robbed, he was determined to defend his own. An unarmed customer came in, got into an argument over the bill, and that normally jovial family friend emptied his gun into the customer.
That is not the kind of world I want my children to live in. A world where a relative handful of crazies may open fire is one thing. A world where anyone, at any moment, may open fire is entirely something else. That's a state of war, a state of siege.
When everyone carries a Glock at his/her hip, how will I separate potential defender from potential attacker? Will they signal their intent by the color of their hats? No, I'd have to consider everyone with an openly-carried gun to be a potential threat, and everyone who may have a concealed weapon to be an even greater threat.
l'd need to be mentally prepared and regularly trained to return deadly-accurate fire on a moment's notice; to accurately distinguish between friend and foe; to behave in such a way that no other armed citizen would accidentally or intentionally open fire... And god help me when my reflexes inevitably decay. No country for old men, indeed!
The fact that armies possess weapons has not deterred war. Police are not immune from attack. Fortified cities are besieged and taken. Armed gangs attack armed gangs. I'm quite sure the majority of Iraqis and Syrians do not believe war is the answer.