There is a cultural difference there, which at one point was relatively small. In the past of Europe medical cadavers were supposed to be confined to the bodies

There is a cultural difference there, which at one point was relatively small. In the past of Europe medical cadavers were supposed to be confined to the bodies of executed criminals. In China historically accounts of western doctors trying to teach noted the reception, tampering with a dead body was abhorred and living criminals were the suggested alternative. Now this is in the distant past and there has been a lot of distance and divergence since then. The Hippocratic Oath has had great influnce in the west, perhaps related to the Greecoroman romanticization. To frankly guess why it survived as a meme was that the taboo against doctors killing sounds essential for trust and relatedly survival. A patient already gives up considerable control and leaves themselves vulnerable and doctors would be regarded with suspicion. It would make heterodox doctor orders something nobody would prefer since 'doctor but specifically without the oath against murdering patients when paid by somebody else' is really suspicious. Doctors already face grief misplaced anger for inevitable patient deaths, as a profession were already tampering with cadavers by neccessity and given prevalent theologies frankly a few steps away from being declared some sort of twisted heathen cult. That "open secret" sounds like an outlandish combination of scapegoating Israel by local powers looking for unity and recycled blood libel. Stop and think about the logistics of assassination, which depends upon surprise and organ harvesting, a delicate and slow process. Why not kill someone with an elaborate tattoo of poisoned ink with that combination? Trying to assassinate somebody in a landlocked city using a killer whale is more plausible. It is up there with hanging a monkey as a French spy in batshit paranoia.