knives don't stab people people stab people!

[possibletarian]

As others have pointed out, a gun only has one purpose, that is to fire a projectile at another object to damage or kill the target.
Automatic weapons only have one function to fire lots of projectiles at another object to damage or kill the target.

To compare gun ownership with owning a truck, a knife, a brick, a baseball bat is just silly.

However the O.P.'s point is well taken, all of them require a nutter at the wrong end of the tool.