My primary point was that you don't blame the gun when someone fires off a negligent round.
Then we agree. You are also correct that no mechanical safety is foolproof. No amount of mechanical safety can overcome unsafe practices. It's the meatware safety that is most important. And unfortunately, it's also the most fallible.
It isn't the gun's fault that a negligent round fires. One should ALWAYS be sure of a clear chamber before any takedown procedure, whether the trigger must be pulled or not. I'd hold short of ridiculing someone who has an ND like this, mostly because any of us can be distracted, but it is certainly the fault of the operator.
It's up to the owner to know the ins and outs of a firearm. 1911 owners need to understand that the short and light trigger pull makes it VERY easy to launch a round. Glock owners need to understand that if the trigger is pulled with a round in the chamber it WILL fire. Every design has its peculiarities. It just so happens that this particular peculiarity is one that is highly unforgiving of a failure to clear the chamber properly, and that's something owners must keep in mind.
My Sigma is like this. I always, ALWAYS double and triple check before stripping it. It's way too easy to get distracted.