Human nature is complex. Even if we do have inclinations toward violence, we also have inclination to empathy, to cooperation, to self-control.
With violence, as with so many other concerns, human nature is the problem, but human nature is also the solution.
We really are creatures of a violent world, biologically speaking - watching violence and learning about it is one of our cognitive drives.
Technology, ideology, and social and cultural changes periodically throw out new forms of violence for humanity to contend with.
As women are empowered, violence can come down, for a number of reasons. By all measures, men are the more violent gender.
All of the violence that doesn't occur doesn't get reported on the news.