Unfortunately, that's because many of us that wish to retain the right to carry a firearm are feeling the ability to do so slipping away. Since I feel that it is my right, as per our constitution, to own a gun I'm willing to fight tooth and nail against anybody that wants to take away my right to do so. For that matter I'm pretty well willing to fight anybody when I feel ANY of my rights begin to slip, and believe me, they're starting to slip ever and ever faster in this country.
In other words, when people start talking about "never having a need for a gun" I, too, skip immediately to the assumption that said people would just as soon see them outlawed. Besides, since when are guns the only thing that criminals use to kill, rape, and steal? What's next, hunting knives? Kitchen Knives? Rope? People with big hands? I mean really, it's just as easy to kill someone with a knife as with a gun, unless you run up on someone with a gun.
On another tangent, never in the history of mankind has one group of people harming another group ever been stopped by anything short of more violence.