The bottom line is that there are laws against shooting people already, except in narrowly defined circumstances.
There are laws against sticking them with knives, bludgeoning them, slasher attacks (as opposed to sticking them), and a host of other methods of depriving a person of a heartbeat, including taking motor vehicles and running them into pedestrians and the misuse of explosives.
Despite all those laws, from making Sarin Gas in trash bags on the subway to blowing up rental vehicles and backpacks full of junk, no one is calling for banning trash bags (except maybe California, and for different reasons), rental vehicles, or backpacks, yet all have been instruments of mass casualty incidents.
The salient difference between those items and guns, is that guns provide (in the right hands) a means to stop the other events.