Let's play the devil's advocate and understand the motive behind it-
The average annual wage of a Chinese citizen is $7,500 USD, whereas the average annual wage of an American is $45,000.
Which means that $400,000 is worth 400,000 x 45,000 / 7,500 = $2,400,000 . And that's only over 23 years so far. You have to keep paying until the day the victim dies. That's the equivalent of $105,000 for Americans per year.
If you refuse to pay, the victim will take you to court and confiscate all your belongings. If you still refuse to get a job to pay, the court will throw your ass in jail and (here is the important part) force your family to pay, indefinitely, until the victim dies.
So are you going to have your family pays $105,000 per year while you sit in jail, or are you going to make sure the victim is dead?
Trust me when I say no one wants to kill another human, but when the law is lay against you in such way, well don't be surprise that humans can override their natural instinct.
(I am from Hong Kong that, while most people there do not share the same sentiment, but can understand the math behind this horrific logic.