The right to maintain an organized militia against political tyranny is also a valid reading of the same amendment. Remember that when you link to that.
Guns are bad, no matter how you want to cut it. I wouldn't even know what to do with a gun myself, knowing exactly what happens afterwards, since it has literally no other function. I've seen how a man died from his gun by shooting himself in the brain. I've dug with trauma surgeons for bullets in the abdomen to find where the bleeding goes. It's never been a good thing and will never ever be a good thing to have something this lethal in a population that is so trigger-happy.
Also, the "more guns, less crimes" idea is at best a myth. Concealed guns do not save lives in situations of crises and panic. It only exacerbates the situation. A crazy will not think of consequences anyway, and concealed guns won't deter them.