I cant believe that the blind illogic of this statement has eluded everyone.
For this someone with kids to blow away the person with a rifle on his shoulder that person would have to be carrying a firearm.
So why would a person carrying a firearm immediately see this person as a threat? For a person to carry a firearm it almost a foregone conclusion that they do not view persons carrying a firearm as being an inherent threat.
"Be polite, be professional, but have a plan to kill everybody you meet." ---USMC Maj. Gen. James Mattis