They helped with traffic control...
It should have never happened, but it's not like they "employeed troops in a firefight".
They probebly have a common "mutual support agreement" and exercise it outside of correct authority.
Remember, those soldiers are also part of that very community where they helped out after a terrible shooting that took 11 lives. Reaching out for help en-mass was probebly smarter than it was stupid.
Don't get too bend outta shape about it.