Answer

I never said such a thing. What I said was that when there is an extreme contradiction—that is, when the moral cost is enormous and irreversible—I would consider the possibility that the Sages did not interpret the Torah correctly. If it is clear that they did not interpret it correctly, there is no obligation to listen to them in such situations (even according to the view that there is an obligation to obey even when they tell you that left is right. I claim that when the moral cost is terrible, everyone would agree that one must not obey an erroneous ruling). Like a religious court that erred regarding an explicit Mishnah. Notice that you yourself wrote that this is a law that is unclear to me. But if the law is in fact clear to me, the situation is different.
Beyond that, the whole process of going to the Sanhedrin and their issuing a ruling is a procedure for clarifying Jewish law. I am not discussing the question of what the Jewish law is, but rather a case where we know what the Jewish law is and it contradicts morality. In such a situation, the question is which prevails. That is not necessarily entrusted to the Sanhedrin. Think of an instruction from a doctor that causes moral harm to someone. The doctor, in his role as doctor, will give that instruction because that is his job in his capacity as a doctor. But I will not necessarily listen to him because of the moral consideration.
When the matter is written explicitly, my assumption is that the Holy One, blessed be He, Himself took the moral cost into account and nevertheless instructed us to act that way. Therefore, there one probably does need to obey the Jewish law. But when it comes to the Sages’ interpretation, there is always the possibility that they erred. The formal obligation to obey them despite their ruling being mistaken cannot justify causing horrific moral wrong.