Last time I was in Lowes probably half the store was carrying a pocket knife which could have been used to kill me, but there was no need to worry. Anyone could have picked up a hammer off the self and wacked me, didn't happen. Everyone of the people in Lowes that day could have been carrying an Uzi and the results would have been the same.
There may be a very few crazies out there, but disarming all those other people won't in the slightest way protect you from them. I could have a tank bunkered in my backyard, but you're just as safe as if it was just a shovel, because I'm not going to use it on you.
Get a grip, murder rates have been falling since medieval times, when the weapon of choice was a knife. Your panic only gives power to and encourages the nuts.