"One dog plus one dog does not equal two dogs...it equals a pack.
Any experience a person has with a particular dog's behavior goes right out the window when dealing with a pack."
You are exactly correct. Many people are killed by dogs in the United States every year. It is not just Pit Bulls or Rotweilers or German Shepherds. It is what is in dogs genes when they get into a pack.
You seldom hear about a person being killed by one dog alone.