That's a ridiculous assertion, and I'd politely ask you not to impress your moral code upon me. When I make a decision to carry a weapon, it's not because I see myself as a protector of the citizenry as a whole. It's to protect me and mine. Simply because I have shouldered that responsibility, I'm not volunteering to protect everyone else that comes my way. They have to decide for themselves what their own safety and security is worth. Selfish? Maybe, but I don't buy into the whole "sheepdog" mentality.
My stance is quite simple. I'm not inclined to put my life on the line for Joe Schmuck, who decides not to look after his own safety, when doing so means that my wife and kids may not have a father coming home to them. If that means that I'm sacrificing my community for the sake of my family, I'm very OK with that. My family is the only flock I worry about.
No, its not a ridiculous assertion by any means. To use your words I'd politely ask you to not impress your immoral code upon me.
Regardless of one's position on bearing arms that doesn't make their life worth any less than anyone else's. And yes, one's primary concern should be their own safety and the needs of their family. Certainly getting yourself killed while attempting to help others is no help at all and leaves your family grieving.
As for me, I prefer to live life by the Golden Rule, do unto others as you would have them do unto you. So, getting back to Joe Schmuck (as you callously named him) I try to remember that he has a family too. And maybe he doesn't normally carry. Or maybe he's working and not allowed to carry. Or maybe he's like many pro-2A'ers and permit holders across the nation who don't carry everyday. Or whatever. But in a mass shooting scenario those people are in a life and death situation by the actions of a suicidal maniac and they are in need. And there is a chance that one or more of those persons could be one of your family members, maybe a brother or sister, or mom or dad, niece or nephew, aunt or uncle. And simply based on carry statistics I know that not everyone of them carries everywhere, everyday. Wouldn't you want someone to come to their aid if ever needed? I know that if they were my family members and an able bodied, trained, armed citizen was around I'd be mighty grateful that they stepped up and helped if they could have.
And no, you shouldn't seek out to help everyone the comes your way, after all superheroes are fiction. But in those rare and dire circumstances that we all hope don't happen to us if an able bodied, trained, armed citizen was around, and could have helped, and turned their back on those people that is simply unconscionable. Period.