A question for the gun rights crowd: When would it become an issue of too easy access to guns?

This past Saturday an 8 year old girl was killed by a shotgun blast.  Allegedly fired by an 11 year old boy, over an argument about puppies.

According to the story going around, now, the boy was denied an opportunity to play with the girl's puppy - and so went into his house, got the loaded shotgun his father kept, and fired it out the window at her.

Now, clearly, there's a lot of things to point fingers at - not least being the boy's insane sense of entitlement.  We can also speak about his obvious control and anger issues, too.  But in my mind had the shotgun not been loaded, unlocked, in a known location, this would not have escalated to the point where the parents of an 8 year old girl are burying her this week.

Are we, as a society, so in love with guns that we're going to defend the right to have them without let, regulation, nor reason above the expectation of sound parenting?  While the 11 yo boy is obviously responsible for his own lethal action, there's also a good case to be made that his parents should also have some accountability.  The mother of the Sandy Hook shooter has been castigated in the press for allowing her son access to her weapons - and she'd kept them locked in a proper gun safe, that he got at only after he killed her.  Obviously there was no convenient straw-buyer to be put through the public trial in that case, to provide a scapegoat for the tragedy.  When William Spengler killed his sister, and several first responders from the West Webster Fire Department and several responding police officers, there was a straw buyer who could be punished with the full extent of the law.

Of course, she's the only person I'm aware of who has been punished by those laws.  There's a current murder case going on where Charlie Tan is accused of killing his father - with a shotgun purchased for the deed, by a friend.  There are no pending straw buyer charges for friend.

So, who will be held accountable for this boy's hair trigger temper and easy access to firearms?  Are we going to continue to vilify anyone labeled as being mentally ill, and blame the parents for not getting their son the counseling or treatment it seems like would have been appropriate?  Or are we going to finally recognize that lethal weapons in the home are lethal weapons and certain precautions are simply good practice that should be automatically taken by anyone who feels the need to have firearms in the house?