Hmm. Personally I think it comes down to what Owen said. There won't be such violence if the benefits of modern society are shared properly. If folks have a job they enjoy; if places of work are also places of education and creative expression; if everyone is guaranteed a basic standard of living; if political control is direct and open equally to all; if streets are clean; if food is wholesome; if schools are individual-centric and of of high standards; if healthcare, both physical and mental, is provided; if this becomes the case for all (if not most) people, gun violence won't plauge us as it does now.
A garden is a good metaphor for society. Because unless the plants have the right external conditions, and unless they don't compete with each other, they won't thrive.