Even when someone has clearly been murdered, it is the medical examiner who confirms death. Some years ago a professor of forensic medicine at Osaka University issued a death certificate for a brain-dead patient, but the police refused to honor it. Whether the police have the authority to change a doctor's determination of death is something for the courts to decide. But the Japanese police interfered as if they had every right to do so. In short, according to society's conventional wisdom it is not necessarily doctors who determine death.
Conventional wisdom is the only possible answer.
This supposed wisdom often takes precedence over the law. They were not doctors, were too old to be either potential donors or potential recipients, had no relatives in need of transplants, were not patients themselves, had probably never touched or even seen a heart, and most likely knew nothing about the brain. As a result, the report issued by the commission took the unusual step of giving equal weight to opinions for and against organ transplants from brain-dead donors. Because, of course, they did not see themselves as having nothing to do with it. They believed they had every right to speak out.