Hi Kiddo,
I never suggested that good parenting will result in Utopia. The royal massacre is totally out of place here. It did not involve shooting children. It was more of a domestic issue within the royal family. If the prince had gone berserk and killed people on the street or gone into a school of totally innocent students and killed them then we could have drawn an analogy. Patricide, Fatricide etc does happen all over the world  and yes Nepal is no different. But i have yet to see a similar type of incident like Columbine, Newtown in Nepal or in Asia. Or am i missing something?  Mind you, Asia has a lot of people with mental health issues and they do not even receive any professional help. But what i believe is that through good parenting in their youth even people with mental health issues can differentiate between right and wrong. If you think about it, getting hold of a gun is not that difficult in Nepal these days. But we do not see such incidents. Now i am not saying there are no killings. But I don't see anything that we can draw a parallel.
To sum it up, IMHO, if value of life is ingrained in you, you will never kill another human being even if you are mentally unstable. To achieve this, good parenting is necessary till the child is a proper adult say 25-30yrs od age.  But teenagers should not be considered as adults.