The old saying, "A picture is worth 1000 words" was as true the day the old sage spoke it in the Chinese temple as it is today. So take a moment and look at all these images. They are a collection of Islamic Terrorists in the process of murdering innocents in futherance of their political, ideological and religious aims. We did not have readily available images of Mateen or Farooq, but if we did, they would look very much like these guys. What are they armed with?
And look at the last image. That belongs to the CT Operators who eliminated one of the terrorists in Paris. Look at the shield they are using. Do you the impacts on the Bataclan Shield? What made those and why were they deploying a shield of that nature?
The bad guys were armed with rifles.
Now, I would like you to set aside ideas about fairness, the American way of things, and the way things ought to be and look for a moment with me at reality...they way things really are, and the way people really are.
Lets look at the LE Perspective:
You are a SWAT operator running to locate an active shooter. You have heard shots and the information you got was a man yelling in Arabic and shooting at people with a rifle. All the briefings and training on these events has involved guys like this, and knowing what you know about rifles, you plan to take no chances. You turn the corner and see a man holding a rifle, pointed in on prostrate body.
Having worked LE in one of the busiest regions in the nation, and SWAT at that, I can predict with 95% certainty that the guy with the rifle is going to get shot, and very likely killed, by the police. Not a 100% guarantee, but an almost 100% under the situations described.
Not fair you say? Well, rain is also wet and fire is also hot. Feel free to complain about it, but that will not change the nature of rain, or fire.
Nor what a human being tasked with hunting down a rifle armed killer - with few other physical descriptors if any - that he has not yet set eyes on and who he knows is in the process of killing everyone. The description he gets on the fly will not be enough to not shoot the good guy that decides to pick up the bad guy's rifle. Even if it is a great description, what the SWAT operator will focus on is "RIFLE".
So lets consider the following -
First let us assume correctly that those reading this are always carrying a pistol, regardless of the sign saying they "should not". And likely, carrying for just such an event. As well, we are not the sort of people to "duck and cover" waiting for the police as history shows that the LE response may easily be delayed from various factors.
Sure there are mitigating factors such as you are unarmed, such as in an airport or some other place where it was physically impossible to "ignore the sign", and you managed to attack, neutralize and disarm the terrorist with your bare hands...or with a knife - and now you are either unarmed...or armed with his rifle. I get it, but understand that those facts will not be relayed to the responders and you run a very high risk of being misidentified.
Next, lets consider that it is not an impossible task to bring down one or more of these people with handgun work, if it is done correctly and the shooter has an adequate level of skill. (To the incessant critics that will say that the "average guy" doesn't have that capability, I ask them to come up with a better solution that does not involve hiding under a desk in tears...in short if your marksmanship sucks, put down the beer and remote and change that).
Once the terrorist is down, and has been shot in the face with at least a half magazine after he is down, unless there are mitigating circumstances dictating doing otherwise, I suggest leaving his rifle where it lays, lest you be confused for one of his compatriots.
Again, it looks like the modern, properly organized handgun is the ticket for modern unplanned counter terrorism.