Another problem with the (NRA) narrative is defensive handguns. Handguns don't reliably stop bullets. "Well, just shoot him first." (Not a strawman, the most common answer to this FAQ) How? One person in this scene showed up knowing there's going to be a massacre here today, and he gets to shoot first. He does, no matter how much you train, the moment you see the gun, he's already got it out. If yours is concealed, and you can see it, you're betting on your wild west quickdraw beating him, and Stopping him before he brings it to battery, and pulls the trigger. How long does it take him to bleed out? Where did you hit him with your snapshot? You don't know, because you can't even be sure when, and where you'll have to take that shot.
If it isn't concealed, then let's just assume that he's at least Studied firefight tactics, and shoots the armed ones first. Even if you manage to Han Solo him, you have to stop him. In one shot, before he gets a shot off. Not just hit him first, kill or incapacitate him, before he gets a shot off. Good luck? This is a fantasy! Not just a fantasy, but one Real Men (And women, I don't know whether to call Real Women, or not. Help me out here, guys, do Real Women play with guns, or do you call them dykes behind their backs?) train for with no experience in actually doing it.
Never mind, this is a surprise gunfight, in a crowded area, and no matter how much you train, you are at a disadvantage. No matter how superior weapons are, he woke up this morning planning to Die in a gunfight. Not just ready for the possibility, he's planned this day, for years, and he's got first draw. You're not that good, nobody is, nor ever was, nobody wins every gunfight, and it's not a fair fight. You are at the disadvantage here, even if it's 1-on-1, and the room is full of targets to soak up every missed shot. He chose it for maximum casualties.
That's if he didn't bring any bombs, or a "Sniper" rifle. (The rifle doesn't make any one a sniper, and any rifle in a sniper's hands is better than any gun in a wannabe's.) That's if he's brave, stupid, and suicidal enough to walk right in, and give you even that much of a chance, he's going to at least try to shoot you first, and hopefully hit someone else if he misses.
It's not even a fight. It's a terror attack, and you're not helping. You're just adding to the terror with this narrative, and playing the hero, instead of thinking about the victims.