A Tragic Senseless Act

On Saturday one man carried out a senseless, horrible and tragic mass murder. The actions of this man are being blamed on many different movements and organizations. My Question is when is an act like this considered exactly for what it is? A sick, insane act by a person who is now responsible for that action. Have we lost the ability to hold each other accountable for individual actions to the point that we automatically blame society for such a thoughtless, wreckless act.