It's important to separate objections to utilitarianism from the obvious fact that it can very be hard to correctly apply the utilitarian calculus. It's partly because of this difficulty that most classical utilitarians thought that people should generally follow commonsense morality and not try to directly apply the utilitarian calculus (which then led to the charge of paternalism and teaching one morality to the masses and another to a supposed elite).
But there are also people who just oppose utilitarianism, like G.E.M. Anscombe. For instance, in https://integrityproject.org/wp-content/uploads/2015/07/mr_t..., she seems to grant that dropping the nuclear bombs on Japan was probably good from a utilitarian perspective (because it saved lives overall) and also to grant that bombing campaigns that necessarily entail massive civilian deaths (including, apparently, area bombing German cities) are morally permissible but still to argue that dropping the nuclear bombs was impermissible because it constituted murder ("intentionally" killing the innocent). But this kind of distinction, which I think is what actual anti-utilitarianism must come to, is hard to even consistently maintain, and I suppose many HN readers would find the effort quixotic.
The first half of your answer presupposes some platonic utilitarian calculus that, if it were applied correctly, would yield moral outcomes. This is very hard to believe. If I look at notable/well-known examples of EA-affiliated people, it is hard to skip by members such as SBF. Did he correctly apply the utilitarian calculus?
It is relatively easy to take the proceeds of a massive fraud, buy a relatively small (as a percentage of the fraud) $ amount of mosquito nets, and save more lives than the lives impacted by your massive theft. Is this a correct application of the utilitarian calculus? What sort of data would we need a priori to do this calculation "correctly"? Do you think he had a careful estimate of the suicide rate of victims of ponzi schemes before perpetuating the fraud, or would any suicide rate have made the decision net [pun intended] moral, as any such victim of fraud would lead to >> 1 net purchased (so you would almost always net save lives).
The above is of course snarky. It is also a best-effort way of analyzing a notable utilitarian's actions. I do not think it would be difficult at all to use this type of argument to argue that SBF's actions net raised utility in the world. If only we all would become fraudsters, then we could truly live in Omelas --- a notable utilitarian paradise.
Yeah, I didn't mean to downplay how hard it is to apply the utilitarian calculus or even to suppose that the bare doctrine of utilitarianism resolves questions about what the ultimate good we should be trying to maximize is. I basically agree that utilitarianism is not a complete recipe for how to live. I just think that it probably gives the correct answer in cases where we can see clearly how to apply it because I'm skeptical of theories like Anscombe's. Which is to say that utilitarianism is a big tent.
Now if we look at EA, the basic tenet of EA seems obvious -- basically just utilitarianism. And from what I've seen, in practice also, EA is a pretty big tent. I don't know the specifics of SBF's case, but I think essentially no one thinks that he acted correctly. I don't know how many mosquito nets he bought, but I agree that if he bought enough, it might be that he net raised utility, and if that is so, it's something to be thankful for. But it doesn't make him some kind of utilitarian saint unless he couldn't have done even more good by some other course of action that wouldn't have hurt the ponzi scheme victims and brought opprobrium on the whole EA movement
This kind of reasoning leads you to reasoning that if he was an ineffective fraudster, it would be less moral, as he would have bought less mosquito nets. So it’s not only moral to do fraud, but you most extremely competently do fraud.
I think this being a reasonable utilitarian point to make is not a point in utilitarianism’s favor.
But there are also people who just oppose utilitarianism, like G.E.M. Anscombe. For instance, in https://integrityproject.org/wp-content/uploads/2015/07/mr_t..., she seems to grant that dropping the nuclear bombs on Japan was probably good from a utilitarian perspective (because it saved lives overall) and also to grant that bombing campaigns that necessarily entail massive civilian deaths (including, apparently, area bombing German cities) are morally permissible but still to argue that dropping the nuclear bombs was impermissible because it constituted murder ("intentionally" killing the innocent). But this kind of distinction, which I think is what actual anti-utilitarianism must come to, is hard to even consistently maintain, and I suppose many HN readers would find the effort quixotic.