I don't blame you at all for being upset . . . I have a very low tolerance for those that will do something like that and then make excuses like "it's not loaded" or "my finger is off the trigger".
I went on too many ambulance and fire rescue calls for shootings - many of which were the result of "unloaded guns". Sorry . . . . but idiots of any age who do such things need to be called on their behavior. It never ceases to amaze me how may shootings there are with "un-loaded" guns or how someone can shoot themselves while cleaning an "un-loaded gun". People like that have never had the experience of having to work on a shooting victim . . . or worse yet . . . having to tell the victim's loved ones that their loved one didn't make it. Proper gun safety is not intended for "just loaded guns" - every firearm should be treated as "if it were loaded".
Frankly, I admire your patience . . . . I'm a believer in letting an individual who is acting in an unsafe manner with a firearm have one warning . . . after that . . . if it continues . . . well . . . they should be told how a weapon can be quickly made into a "metallic suppository".