There is a difference between defensive violence and offensive violence. For example, do you believe that you own your body? I do, and I would defend myself if necessary. I would only use violence against those that are threatening me though. If you hold that you own your body, then by extension you own the output of the things you create with your body.

There has been much thought on this line of philosophy, it's called the non-aggression principle (https://en.wikipedia.org/wiki/Non-aggression_principle)