What possible use is it to the taxpayer to know who was affected by what health condition? NASA knows who the person is, if there is any lesson to be learned this policy isn't stopping them. What lesson do you, random citizen, expect to learn? What would you do differently if you had access to this information?

If it is policy to overshare medical details, that might lead astronauts to delay or refuse to give medical information that does matter to the mission. Before we talk at all of medical ethics, on purely pragmatic grounds this information ought to be confidential.