This is completely false. Guns can be used for anything to be done with range such as plinking, hunting, defensive use and many times just producing a gun will disengage an assailant, it can be used for predator control.2) Knives have multiple uses. Gun's only use is to either kill, injure, or threaten
And this argument is really just beat to death. It's time for people to retire it, a gun and an RPG are completely different, as are chemical weapons.3) If the argument for owning guns is that guns deter violence, you can also argue that even more deadly weapons (RPG's, chemical weapons, etc) could do an even better job at deterring violence, but an overwhelming majority of people, including pro-gun supporters, would agree that these weapons should not be made available to the public.