the problem here is that mortality rate is not correlated/normalized with the patient risk factor. the problem lies in the performance indicator itself, not strictly people trying to optimizing for what they are asked for. it is likely inhumane to refuse patients that have slightly above average risk - even if there are some considerations to be had, like having replacement organs go to waste, but that is already covered by the donor lists queues - but given people can find themselves out of work for having bad mortality rates, optimizing for the performance indicator it's the only logical conclusion.

also, normalizing for the patient risk will likely just lead to people overstating patient risk, because once you reduce performance to an index, people will focus on what's measured before on what the intended goal for the measurement is.