The "it's the person not the gun" argument is one that seems to be commonly offered up as some sort of explanation. And there are many people perfectly safe and capable of owning a firearm without hurting others.
However, whether thats a good argument or not, it should be obvious that it's very hard to shoot someone with a gun that doesn't exist.
What it comes down to is a basic choice of opinion:
a) I find gun crime to be an acceptable inevitable consequence of the having firearms in circulation
b) I do not find gun crime to be a acceptable inevitable consequence of having firearms in circulation.
Because for all the arguments it really comes down to that. For all the wishful thinking in the world, and for every 'safely' owned gun out there, you just can't have it both ways i'm afraid.