Because he was ambushed and the shooter had armor on
More armed citizens being there would most likely have changed that entire event
Just like i said in that thread, the concept of "cover fire" is a strategic military tactic for a reason.
The more people shooting at him, the less free he is to run around killing civilians
Do you think a hive mind emerges when armed people are shopping, where they all instantly know how to communicate with each other to pin down an active threat.
The clear distinction between the military tactic you're describing and random armed people shopping should be obvious. You can't really strategize without communication. And if someone is wearing armor, they're likely anticipating being shot, unlike the armed shoppers with handguns on their person.
The guard in that store engaged and shot the shooter, the guard of any store is likely going to be the most trained person for this task, and while he put up a good effort, he was outmatched by someone that anticipated being shot at. Your answer is more people who aren't prepared to be shot, shooting at a person that accepted and
prepared for the possibility that he might be shot before he even entered the store.
