To this I would say, you're changing the subject. The question is, “should the government ban things because people don't need them". What is the legal precedent for that?
There's plenty of legal precedent of governments banning things with no need, and ostensibly for reasons of public safety. Off the top of my head, asbestos, smoking in public places, marijuana, internet gambling, salvia divinorum, using a cell phone while driving, etc.
The most recent and obvious example would be the prohibition of pre-mixed caffeinated alcoholic beverages such as FourLoko, despite the fact that there is no actual evidence that such drinks are harmful in any way at all, and it's still legal to make a Jack and Coke or Red Bull and vodka.
The argument isn't one of whether the government should be free to ban things because "they" don't perceive a need for them. Attempting to argue your position from that angle isn't going to work, because fence-sitters who favor a ban believe there are viable public safety reasons for instituting a ban, and don't give any further thought to the implications of such a law because it wouldn't personally affect them.
As for magazines killing people, that's more absurd than the argument that guns kill people. I have never seen a gun load itself, aim itself, and pull its own trigger. The day I see that happen, I'll support banning firearms. Until then, the argument that inanimate objects kill things independent of human intervention is illogical.
Trying to claim that the opposition is attempting to anthropomorphize guns isn't going to win you any converts. The average person knows that guns do not in and of themselves cause death, but they are probably inclined to believe that access to certain kinds of guns or accessories makes it easier to cause mayhem.
Most people, especially non-shooters, will intuitively believe that it's easier to kill more people with higher capacity magazines than without. From there, it's fairly logical to conclude that if there's no compelling reason for ownership of these magazines, and if removing them from public circulation will keep people like Jared Loughner from killing as many people, it would seem completely reasonable to support a ban on them.
Fundamentally that's what many people in this thread aren't understanding. There's no attempt to actually look at the arguments in favor of a ban and rationally deconstruct them. There's no analysis or thought. Instead it's all internet chest-thumping, which I suppose must be cathartic for some, but should never, ever be mistaken for an actual debate tactic that will swing people over to your viewpoint.
