Zappa, the problem here is that you address us as "gun nuts" and then expect us to take you seriously.
Those of us who are serious gun buffs take firearm safety very seriously. There are some very basic rules that must be followed. When idiots ignore these rules and misuse a firearm or neglect to store it safely, you want to blame all of us.
These parents are guilty of negligent homicide. Nothing short of banning all privately owned firearms would have prevented this tragedy. I looked into buying one of these Cricket .22 rifles when my daughter was younger, but decided she could do better with another type of rifle. The gun involved is about as safe as they come. It is a small, single shot rifle that requires you manually cock it after you load it. I doubt very seriously that a 5 year old could have cocked it, so I am betting they left it, not only loaded, but cocked as well.
I have bought numeroud new firearms over the years. Not one single gun I have purchased in the last 15+ years did not come with some sort of lock mechanism. Not a single one.