They didn't have to fire a shot. They were known to be armed
Ya, the feds got the kiddies public government schools running in panic when they see pictures of guns. No doubt.
So you think this is a perfectly legitimate shoot, because they believed they were possibly armed at the time. Go it!
I'd say it was a legitimate concern:
They were of the wrong demographic to get away with it. It's not like they were the Black Panthers or Black Lives Matter types.
Being westerners who presumably knew which end of the tube the rounds come out of, they posed a credible threat.