I think we need to not let emotion's get in the way of looking at the situation.
This is just an occurrence that has been repeated many times throughout history. If one enters another home unannounced, then they are liable to be killed. It is nature. Animals are territorial, and I don't see any reason why we don't have animal instincts.
A stranger enters one's home. One does not know the stranger's intentions, so one should have no reason to not fear for her or his life. This is fact. One will fear for one's life, and one has the right to fight for one's life. It doesn't matter how old one is, whether they are ten or forty, the basic instinct is to survive. This is the basic instinct of every single living organism on this Earth. Survive!
So when a couple of fifteen year olds enter a house to steal, a ten year will certainly fear for his life, because this is instinct. The ten year old can wait for the police to come, and risk not only his life, but also his sisters, or the ten year old may take vigilant action himself to ensure their own survival.
What would you do? We all can say we would call the police and scare them off, because we are older and smarter. But what would you do if you were ten? The intruders are older than you. You may die. They may also kill your sister. What are you going to do to ensure your survival?
In the end, the intruders were shot. This is nothing new. One feared for his life for good reason, and the intruder paid the ultimate consequence for unannounced entry. Simple as that.
Yes, the story isn't pretty. Nobody could have been hurt. But this isn't a pretty world. It never has been. Intruders can be killed because it invokes one's right to survival. A person will do anything to survive.
So can we throw all the petty bureaucratic politics out the window please? It misses the point!!!