You can take away machetes too, and some autistic murderous sonofagun will just take a lawn mower blade, wrap duct tape around one end for a handle, sharpen up the other end with a file, and go split somebody’s head in two like a melon.
But people kill people. Sad, but true. As you point out, taking away one tool is not a real solution. There are plenty of other tools that come to hand.