The point of his argument is not that under certain exceptional conditions surgeons should kill people to harvest their organs to save more lives, but precisely that any sort of formal pledge or personal obligation or non-utilitarian moral code can be betrayed if that leads to higher expected utility; and that it is prudent to lie about your true intentions and convictions if you think that is a precondition to achieving greater total utility. It is very much an argument in favor of a fundamentally untrustworthy and conspiratorial mindset, and not just specifically on the issue of saving lives – like the trolley problem, this is only an illustration. This applies to utility in general, and thus to all instrumental preconditions for creating it: to money, power, anything; therefore, any act of a Singerian should be suspected as part of an instrumentally useful scheme to secure a position to achieve more utility. This applies the most to pretenses of having integrity, valuing promises or even some kind of sentimental loyalty.
People who profess to believe in Singerian doctrine can not be trusted to mean what they are saying, because you cannot know what sort of a convoluted scheme to maximize total utility they have imagined that could necessitate deception in a particular case.
Again, his follower Sam Bankman-Fried has demonstrated this very clearly by defrauding his clients and appropriating money for the purposes of Effective Altruism and AI Alignment movements, and then by piling an absurd lie on an absurd lie. Singer defends the teaching by claiming, contrary to his somewhat more sophisticated argument, that "honesty is the best policy"[0]. This is what he, in his article, describes as morality for children – that is, the immature people who cannot be trusted to make consequentialist decisions and should be taught deontology.
> and he believes you could never recommend the action to others
Oh. Okay, so he says that it is the morally correct course of action logically following from moral philosophy he has been advancing and propagandizing all his life, but [generic] you should not recommend it to others. How is that very claim not such a recommendation? What is the meaning of this sophistry?
Perhaps it serves to separate those who can practice the shallowest Straussian reading from those who are effectively children.
0. https://www.theguardian.com/education/2022/dec/24/giving-goo...