In a country of 350 Million people, one nutjob goes on an insane murder rampage, and suddenly the left sees this as an opportunity to confiscate everybody's guns for the good of the collective. The Left sees this as symptomatic of our society rather than what it really is; one mentally ill sicko. We want to believe that we could have somehow prevented this tragedy if only we understood what the shooter was thinking.
As Chris Rock so aptly put it, "Whatever happened to plain 'ol 'crazy'?"
The only person at fault here is the shooter.