If the father had any sense, he would have handled the entire thing differently. Unless the homeowner was clearly off his nut, the father should have explained gun rights and property rights to the girl and amended his approach to knocking on strangers' doors. If the father had not become so outraged at the sight of the gun, he might have made a friend.
The homeowner could have had reason to be suspicious. These days, you do not know whom to trust. People impersonate utility workers, police, pregnant women and also use children as bait in order to commit crimes.
With all the home invasion robberies going on these days you never know, when the next faint knock on the door may escalate into the door being kicked in and an entire family being held at gunpoint.
It is better to be safe, than sorry or perhaps even dead as I would not be surprised if there is a street gang out there that dresses up like Girl Scouts in order to gain homeowners confidence.
You make excellent points.
I wonder if the firearm was actually pointed at the father and daughter or if the father wigged out when he saw the firearm and thought it was pointed at them.