@izzythepush,
Let me see
One can plan to kill by running over someone. It is a bit complicated as it will be timecosuming to hit the right moment without a witness.
Knives - you have to get close and look the person in the eye - so to say. You have to know where to hit so it is a deadly wound.
Poison - where to get poison is the first question and how to do it if you do not live in the household of that person.
And few other ways, which all mostly means you have to get close to the person, they are time consuming or not really dependedly
Shooting is fastes, can be done from far away and you do not have to get close to the person.
It can be done by any coward in the world - so let us protect ourselves from these cowards and get rid of guns in the hands of a bunch of sheep.