5-year-old shoots 2-year-old sister in Kentucky with rifle he got as a gift

This jumped out at me:

In southern Kentucky, where children get their first guns even before they start first grade, Stephanie Sparks paid little attention as her 5-year-old son, Kristian, played with the rifle he was given last year. Then, as she stepped onto the front porch while cleaning the kitchen, “she heard the gun go off,” a coroner said.

WTF? A five year old is playing with a real gun, and his mother ignores him?