If a kid gets into the cleaning chemicals and downs a bottle of bleach, does anybody talk about banning bleach? Of course not, in that case it's the parents' fault for being stupid.
Tangent the first: but the purpose of a gun is to kill people, not to clean things! Actually, you could argue that the original purpose of guns was to kill animals for food or self-defense; but that's irrelevant. Guns are the technological response to an imperfect world where violence happens, and they allow me to level the playing field between me and the person who's trying to break into my house or rape me.
Tangent the second: a person has to be pretty damned stupid to leave a loaded gun where a kid can get to it. Hell, leave the magazine next to the gun, even - it takes very little time to load it in the case of necessity, but sufficient manual dexterity that if the kid who finds it can do it, he's old enough to be taken to a range and taught proper handling and respect for firearms.
Tangent the third: I may not be the most paranoid parent in the world - I may not do as much childproofing as is considered appropriate - but if Aiden injures himself on something I leave accessible, you know what? It's my fault. And I'll damn well deal with the consequences.
Hell, barring extreme injury or death, Aiden has to hurt himself on the things around him in order to learn where the boundaries are. I have to allow him to fall down a couple of steps occasionally so he learns to be careful on stairs. I do him no good by ensconcing him in bubble wrap until the day I have to take it off and he has no idea how to deal with the real world.
Now, a bump on the head is obviously a far cry from a bullet to the chest, but where exactly does that line fall, and who decides? There are parents out there who would think me horrible for allowing him to ever hit his head, just as there are those who think I'm coddling him unconscionably by picking him up whenever he wants. But he's my child, so I decide where that line falls, and I deal with the consequences if I misjudge.
Sure, tragedies happen. Risks happen. And sure, if I appear to have a pattern of severe misjudgement, the government can come and take him away from me - but the government is even more ill-advised to keep me from making any mistakes at all than I am ill-advised to keep my son out of any and all danger forever, because the government sure as hell ain't my mommy.