The problem is that people are not statistics. It may sound reasonable on the surface to say that this heuristic minimizes harm on average because she doesn't perform unnecessary interventions on the 99.9%. However, there are still actual human beings in the 0.1% who are harmed. What you're really saying is that if a group of people is small enough, it's fair for them to suffer preventable harm if preventing it would expose the larger group of people to risk.
I'm not going to argue about whether that is true or not, because I think that clearly depends on many factors and may be unanswerable. But as a member of a minority group who is often denied health care, it is often denied for this very reason. If the wrong person is prescribed this treatment, it is harmful. I'm just saying that when you're in the 0.1%, it can be difficult to accept the idea that you have to sacrifice yourself because someone in the 99.9% might be at risk otherwise.
I'm not going to argue about whether that is true or not, because I think that clearly depends on many factors and may be unanswerable. But as a member of a minority group who is often denied health care, it is often denied for this very reason. If the wrong person is prescribed this treatment, it is harmful. I'm just saying that when you're in the 0.1%, it can be difficult to accept the idea that you have to sacrifice yourself because someone in the 99.9% might be at risk otherwise.