I'd recommend the book The Better Angels of our Nature by Steven Pinker. The article reminded me of it, but Pinker demonstrates why violence in our society has decreased over time (even though many people would intuitively think it's the opposite).
It's always fascinating to me that when this question comes up (are we going downhill or uphill?) the answer inevitably turns to violence. Is violence the pinnacle of evil? Is nothing worse than violence? What about mental illness? Isolation? Separation from your family? Lack of meaningful cultural practices?