Once again, we have a high profile shooting, and once again, the hysteria is out in force.
Let's start with some facts:  If you don't shoot, or have only occasionally shot on a range, then your opinion on how useful an armed respondent would be is garbage.  If you don't drive a car, you aren't qualified to tell professional drivers what they should have done in an accident.
Seriously, shut up, you're an idiot.
Second, everything is a cost-benefit and risk analysis.  Would a defensive shooter have made a difference? We can never know. We can know that it has helped before.
Here are some ways it can help:
The defensive shooter engages the hostile. The hostile must choose to ignore, take cover, or return fire.
If he chooses to ignore it, he remains a target and the odds of him being shot increase, and if he is shot, the engagement ends, and no further lives are lost. If this happens before he quits or runs out of ammo, it is a NET POSITIVE for the group.
If he takes cover, he is not shooting for a few moments, and in that few moments, more people can escape or formulate an attack. (Barstools can be as deadly as bullets, when thrown or swung.)  NET POSITIVE.
If he returns fire, anyone not in the cone near the defensive shooter is not being shot at. This is a NET POSITIVE for all those people, and a slight negative for those in the defender's immediate position.
It is possible the defender will hit a bystander in the process.  However, as he is deliberately choosing a single hostile target, the odds still improve for the remainder, and if the hostile is hit, the engagement stops. This is probably still a net positive.
The defender may be hit. Negative for him, but he accepted that risk. And in those few seconds, the fact is that more victims can escape or respond. This is still a NET POSITIVE for the GROUP.
Yes, the defender may decide his best course of action is to flee. If so...there is no negative nor positive for the group. They remain as they were.
But, this assumes an engagement takes place. Knowing certain areas contain a lot of defensive shooters, attackers tend to avoid them. NET POSITIVE for the group.
The only way to imagine a major negative is to assume that everyone carrying a gun for defense is some psychotic nutjob just waiting to break and spray bullets. There are zero studies or statistics to support this allegation.
This belief comes about from several issues. First, hoplophobia--a fear of weapons.  
Occasionally, it comes from projection. A person with poor impulse control assumes everyone else likewise is prone to outbursts, and of course, if they have a gun, they might act out with it, even though that occurence is demonstrably very rare. The overwhelming majority public and/or mass shootings are premeditated. They even frequently project their small penises into the argument. (Yes, that was deliberate contempt and turnabout on my part.)
Most commonly, it comes from fear and helplessness.  The promoter of these memes knows that in such an event, they'd be helpless, crying, and nothing but a victim waiting to be slaughtered.  More terrifying than that is the notion that NOT EVERYONE IS.  Some people might actually be able to control such a situation.  This means those people are more competent than the poster. It's a frightening notion that random death can visit us, but more offensive and jealous-making is the idea that it isn't just random, that some can change the odds in their favor and not be victims.
The sheep mentality, particularly among "liberals," is that everyone must be equal--equally poor, equally ignorant, equally helpless.
The only thing more outrageous than a killer is inequality, wherein better people (sometimes) survive. The most important thing to these people is to convince the competent that they're really not, or at least convince themselves of that, even if it takes trite, ignorant meme wars and blocking those who'd inform them otherwise.
They don't want education, they cherish their ignorance and fear. 
And they're what's wrong with humanity.
While some say we should pity them, I hold that their deliberate, cherished ignorance and cowardice makes them unsalvageable.
Simply remind them that they're worthless cowards, and be the best prepapred person you can be.  It may not matter, but it will not hurt.
BTW, if every building has fire extinguishers, why do we still have fires?
 
 
