"The unborn” are a convenient group of people to advocate for. They never make demands of you; they are morally uncomplicated, unlike the incarcerated, addicted, or the chronically poor; they don’t resent your condescension or complain that you are not politically correct; unlike widows, they don’t ask you to question patriarchy; unlike orphans, they don’t need money, education, or childcare; unlike aliens, they don’t bring all that racial, cultural, and religious baggage that you dislike; they allow you to feel good about yourself without any work at creating or maintaining relationships; and when they are born, you can forget about them, because they cease to be unborn. You can love the unborn and advocate for them without substantially challenging your own wealth, power, or privilege, without re-imagining social structures, apologizing, or making reparations to anyone. They are, in short, the perfect people to love if you want to claim you love Jesus, but actually dislike people who breathe. Prisoners? Immigrants? The sick? The poor? Widows? Orphans? All the groups that are specifically mentioned in the Bible? They all get thrown under the bus for the unborn. - David Barbary, Methodist pastor
It certainly rings true for white American evangelicals, but it quickly occurred to me it applies pretty well to longtermists too. Centering the well-being of far-future simulated super-humans repulses me, but it seems very compelling to the majority of the EA cult.
Short answer: "majority" is hyperbolic, sure. But it is an elite conviction espoused by leading lights like Nick Beckstead. You say the math is "basically always" based on flesh and blood humans but when the exception is the ur-texts of the philosophy, counting statistics may be insufficient. You can't really get more inner sanctum than Beckstead.
Hell, even 80000 hours (an org meant to be a legible and appealing gateway to EA) has openly grappled with whether global health should be deprioritized in favor of so-called suffering-risks, exemplified by that episode of Black Mirror where Don Draper indefinitely tortures a digital clone of a woman into subjugation. I can't find the original post, formerly linked to from their home page, but they do still link to this talk presenting that original scenario as a grave issue demanding present-day attention.