It sounds trite by now but it's very true: guns (and weapons in general) don't kill people, people kill people.
Humans are smart enough to turn just about any object into a lethal weapon. Sticks and rocks worked great for hundreds of thousands of years ... until some of the other humans got bigger sticks and rocks.
The jaw of a donkey has been used as a weapon of mass destruction.
Even if you manage to get rid of everything that could be used as a weapon, we still have our hands, feet, teeth, &c.
Banning weapons and expecting violence to decrease is like banning sex ed and expecting the teen birthrate to decline. Or expecting Communism/Socialism to work in the real world. YMMV