Actually the term "to bear arms" was almost exclusively a military idiom in the 18th century...
But do be sure to tell these idiots to explain that interpretation to SWAT when they're tackled, cuffed, and booked if they do in fact go through with this hairbrained scheme.
We live in a police state.
The place to challenge unconstitutional acts by the state is in the courts.
First off, LOADED weapons are stupid. Anyone carrying a loaded weapon is asking for trouble. If it's loaded, keep it holstered - unless you're planning to discharge the weapon. I have no problem with concealed carry, and in fact it makes everyone safer - BUT that weapon stays in it's holster unless there is a need to fire it.
Leftists are stupid - it's why they're leftists. But the reason that rifles with detachable mags are SAFER than those with internal magazines is that a loaded mag may be carried OUT OF THE WEAPON. If one is going to carry an AR15, keep the mag out of it.