The most important of Singer's writings, in my opinion, is "Secrecy in Consequentialism"[0], mentioned in this podcast too, though not the crucial part, which I will present without further comment except that this paper should make any utterance from Singer or any of his followers (for example, SBF) inherently untrustworthy.

> There are acts which are right only if no one – or virtually no one – will get to know about them. The rightness of an act, in other words, may depend on its secrecy. This can have implications for how often, and in what circumstances, such an act may be done.

> Some people know better, or can learn better, than others what it is right to do in certain circumstances.

> There are at least two different sets of instruction, or moral codes, suitable for the different categories of people. This raises the question whether there are also different standards by which we should judge what people do.

> Though the consequentialist believes that acts are right only if they have consequences at least as good as anything else the agent could have done, the consequentialist may need to discourage others from embracing consequentialism. …

> The idea that it is better if some moral views are not widely known was not invented by Sidgwick. In Plato’s Republic, Socrates proposes that ordinary people be brought up to believe that everyone is born ‘from the earth’ into one of three classes, gold, silver or bronze, and living justly consists in doing what is in their nature. Only the philosopher-rulers will know that this is really a myth, a ‘noble lie’. …

> Esoteric morality is a necessary part of a consequentialist theory, and all of the points above can be defended. …

> One of the most common objections to consequentialism is based on a hypothetical situation in which a surgeon has to do a delicate brain operation on a patient who happens to be the ideal organ donor for four other patients in the hospital, each of whom will die shortly unless they receive, respectively, a heart, a liver, and – for two of them – a kidney. The doctor is highly skilled, and is conﬁdent of her ability to carry out the brain surgery successfully. If she does, her patient will lead a more or less normal life.

> But because the operation is a delicate one, no one could blame her, or have any reason to suspect anything, if the patient were to die on the operating table. Moreover, the hospital is experienced in organ transplantation, and the surgeon knows that if the patient were to die, the recipients of the patient’s organs would soon be able to go home and lead a more or less normal life. The surgeon knows no other details about her patient or the other patients, such as whether they are married, have children, or are about to discover a cure for cancer. In these circumstances, critics of consequentialism say, the consequentialist must think that the doctor ought to kill her patient, since in that way four lives will be saved, and only one lost, and this must be better than four dying and only one being saved. But, so the objection runs, it is obviously morally wrong for the surgeon to kill her patient, and any moral theory that says the contrary must be rejected.

> We agree that the consequentialist must accept that, in these circumstances, the right thing for the surgeon to do would be to kill the one to save the four, but we do not agree that this means that consequentialism should be rejected. We think, on the contrary, that the appearance of unacceptability here comes from the fact that this is one of those rare cases in which the action is right only if perfect secrecy can be expected. Moreover, it is not an action that should be recommended to others.

0. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-9329....