The item doesn't have to be a weapon for it to be used as one.

I didn't ask for a shortbow. I just asked for the materials to craft one myself. If anyone here knew how to make bombs or other weapons, they can likely get the materials from the Sheriff. I don't think he's against it. The loophole is he isn't directly helping us murder. We're making the murder weapons ourselves.

[But, honestly...] There are also ways for people to kill others without special weapons. If someone knows how to kill.

Batman knows how to kill with his bare hands. He just chooses not to do it.