There's like, a million things in a household that you don't want your kids to touch. Knives, car keys, (guns), glass objects, etc. They can hurt themselves with all of them. This was a 6 year old kid, not a 6 month old kid. We're not talking about a toddler, this guy knew he was holding a gun and knew that if he depressed the trigger that it would fire. It's entirely possible that the gun was locked up and the kid found the keys, unlocked the safe, took out the gun not realizing it was loaded, and shot himself.