This asks the wrong question. The real question is, why on earth should the girl have been left off the eligible list if her doctors agreed that she had a good to excellent chance of successfully using a pair of adult lungs?
The rules about who gets transplants should be *guidelines,* not hard and fast rules that don’t take individual circumstances into account.
You're correct, of course. But there is a reason for "hard and fast rules" -- they are less subject to litigation.
A doctor or administrator who practices discretion in life and death matters such as these is leaving himself wide open to a legal challenge that he committed a "mistake". In a "judgment call", the attorney's judgment is equal to the professional's judgment -- under the law.
It's the same reason many schools practice "zero tolerance". Once they make a judgment call, little Johnny's parents are going to bring suit.
The substitution of "hard and fast rules" for what should be guidelines is the price of a litigious society.