You make some good points.
Much of this discussion, though, assumes that you’re the only one armed - the only armed law-abiding citizen, that is. And in the situation in question in NH, it appears there’s only one armed fellow in the crowd.
If there were, say, a few dozen other folks armed, we wouldn’t be discussing whether a thug could grab his gun and seize control of the situation. Likewise, if a mugger could reasonably expect to be confronted by a handful of armed citizens any time he accosts one person on the street, there’d be a lot fewer muggings going on.
The point is this: We need to outnumber and outgun the enemies of civil society. And we need to make sure they know it.
Being here in New Hampshire, I can positively GUARANTEE you that he was not the only one armed. MSNBC flacks probably just panicked too much to notice anyone other than the first armed person they saw.