Why did this happen?

Julia Prodis Sulek and Ken McLaughlin on Minutes of horror as Turlock father beats, kills his son:

Six-and-a-half minutes for two men to try to stop a father from beating "the demons" out of his two-year-old son in the middle of a dark country road. Six-and-a-half minutes for a young woman to crouch in her car and watch in helpless shock. Six-and-a-half minutes for a police officer to land in a helicopter, run across a cow pasture, and shoot the man squarely in the forehead.

Six-and-a-half minutes of horror.

I wish I could think of something more to say, but I just don't think that words could adequately express the rage, horror and sadness I feel right now.

Why?  Why?  Why?