I also got the sense that some kind of averaging consideration (or inverse prioritarianism, where the flourishing of the ~90th percentile along some dimension) was the essential thing for vitalists. Helping the weakest be stronger doesn't count when your concern is the peak strength of the strongest.
It's very much an aesthetically grounded, rather than experientially- or scale-grounded ethics.
I think the bigger issue with Scotts post is that the "vitalist advocate" he is responding to appears to be an (imo quite vile) alt-right neoreactionary. Like, of course there are deviations between an altruist and a "former" white nationalist alt-right blogger who chose "walt bismarck" as their pseudonym.
And I get that he's trying a "gotcha" here, to say that if vitalists truly believed in making people strong they'd be donating to malaria nets, but, his argument on that front sucks. Like, he characterises a "hyperspecific" form of vitalist to be “building as many tanks as possible”. Do we really think the alt-right shithead is going to agree with that characterisation? He's just redefined vitalism as a different form of altruism.
Summary: In his most recent post (“Altruism and Vitalism as Fellow Travelers”), Scott Alexander tries to reconcile EA-style altruism with Nietzschean “vitalism.” He claims that the philosophies argue for different goals only in extreme cases, while having similar goals in reality. But his definition of vitalism misses the point: the goal isn’t to increase vital traits in the population, but to uplift rather than impede the vital type of person. So he fails to realize that the philosophies have different goals even in reality. They can still be reconciled but not in the way he thinks.
The problem comes from his definitions:
Define altruism as “try to increase happiness and decrease suffering across a society” and vitalism as “try to increase strength and decrease weakness across a society”, where “strength” is defined as ability to achieve goals (and, in a tie-breaker, ability to win wars).
But this misunderstands Nietzsche. From “Nietzsche’s Morality in Plain English”:
Nietzsche’s overarching project is the “revaluation of all values”: a critique of herd morality (which he typically just refers to as “morality”) on the grounds that it’s hostile to the flourishing of the best type of person.
…
He advances what Leiter calls a “doctrine of types” where everyone is some type of guy and the type of guy you are determines the kind of life you can lead, and that you’ll hold whatever philosophical or moral beliefs will favor your interests. He doesn’t hold any extreme “determinist” position but is broadly fatalistic about how your type-facts circumscribe and set limits on the kind of person you’ll be and the beliefs you’ll hold, within which you can be influenced by your environment and values.
The vitalist position would more likely hold that some people are capable of doing great things, and others aren’t. So better definitions are:
Scott gives the extreme example of altruism as WALL-E’s “morbidly obese people on heroin drips.” His vitalist equivalent is “building as many tanks as possible” or people in the previous scenario on testosterone drips instead. But a better example of the extreme vitalism would involve an extremely unequal society where the higher type is distinguished with some kind of test and then allowed to run roughshod over the rest. Something like Sparta with its 10% citizens and 90% slaves, but with the citizen/slave distinction decided by some test for higher vs. lower type. The citizens are free to flourish in the solitude of their Nietzschean citadel writing poetry or whatever, while the slaves are prevented from getting in their way.
Scott argues that in reality there isn’t much room for disagreement, but a lot of policies pit altruism against vitalism, because altruism doesn’t value aesthetic spectacle and genius while vitalism considers it very important. The top geniuses could be given more educational resources in youth and more tax breaks in life. They could alternatively be kept poor and preventing from socializing or having fun so that they don’t become decadent and stop creating art. The poorest and least healthy could be deprioritized; right now, a majority of federal-government spending goes into social services and insurance for the sick, poor, and elderly.
Scott says that if he “wanted to strengthen humanity as much as possible, [he’d] work on economic development, curing diseases, or technological progress.” But an assumption of vitalism is that only the highest type of person, the creative genius, is capable of achieving great things like these, which means it’s essential not to get in their way.
Dealing with this assumption of vitalism is essential if Scott hopes to reconcile it with altruism. You can redefine the value of the highest type as being their public usefulness rather than their aesthetic spectacle, but it’s difficult to find a synthesis unless the vitalist assumption that only some people produce value happens to overlap with some empirical claim the altruist can defend, like if it happens to be that some people are suitable to advance humanity while others can only possibly get in the way. Otherwise there’s no reconciling, because the vitalist’s concern of nihilism, the looming threat of a meaningless existence that can be recovered only by a few creative geniuses, will always seem ridiculous to the utilitarian.
For those wanting a quick encapsulation of Nietzsche's morality, I recommend Arjun's other post on the topic. It's both unusually succinct and well-written.