Yeah but they would just use something else. They would pick up a knife, they would use a bat, murder has been happening for a long time? But cruel and stupid people will always find a way to exact their form of justice be it with a gun or not.
The point is these people plan to do what they are doing and if it's hard to get a gun they will find another way.
Yes gun laws in the USA are stupid and they allow stupid people to own guns, some legally some illegally.
People say they have guns in their homes for safety (bullshit) how is keeping a firearm I your house safe?
But if you are intent on killing another person they will use a gun, a knife a sword or just push somebody in front of a train. The method does not matter, what matters is these stupid people intent on causing harm to another human. Whether they use a gun or not.