---spoken like a true pro-lifer
The law is like this because it values a person's life more than someone's property. And it should. The fact that you don't understand this shows how warped your morality is - the fact that you think it's OK to try to end someone's life because they tried to take something from you.
GhostWriter says the reason murder is immoral is because it's violating someone's property rights over their own, er life.