"Equality" in the sense of equal rights, yes. Not in the sense of equal capabilities. Classical liberalism, as exemplified in documents like the Declaration of Independence, was based on the idea that, even though people have differences in ability, those differences do not give any person a right to rule over any other person. That's where the justification for "self rule" comes from.
Since this reasoning already recognizes that people have differences in ability, "science" showing that people have differences in ability (did we really need "science" to tell us this? isn't it obvious?) does not invalidate the reasoning at all.
"It's bad to kill people" -- this statement is also false. There's no logical necessity that says its bad to kill people, it's only a utility calculation (whether you get caught, what the profit will be vs repercussions etc).
Still if you don't live your life by this assumption (that killing people is bad) you will get many important things wrong.
The basic moral imperatives should not be based on them being objectively true, but on what kind of world we want to live in.
"All men are created equal" doesn't mean "everybody is as tall" or "as strong" or "as smart". Obviously those who wrote it knew that already. It also doesn't mean a person without qualifications should get to work as a doctor just as well as someone with a M.D. diploma. They knew that too.
It just means that all people are equally worth, not to some utility function, but absolutely as human beings.
In order to believe that worth can be determined independent of a utility function, you need a standard of absolute worth. Even religious statements of worth are based on utility to the deity. Biological statements of worth regard utility toward the population or ecosystem. I can't think of a non-utilitarian standard of worth that isn't arbitrary, can you?
Or you can just dispense with the notion of worth of a person as person altogether -- then you don't need to "determine" anything. That's what the "equal" part means in that sentence: don't try to determine".
You can determine the skills of a surgeon, the education of a scholar, the speed of an athlete, the voice of an actor, the coding skills of a developer, etc.
But you should not try to determine the worth of a person as person. That is, when you don't care to measure something something specific, you should not consider someone inferior.
>Even religious statements of worth are based on utility to the deity.
Not really, at least not in the religions I've known. At least in (non-protestant) christianity people have absolute utility.
Christianity allocates some souls to hell and others to heaven. Isn't that an expression of differential utility to God's purpose?
> But you should not try to determine the worth of a person as person
I agree that should usually be the case before the law, and in that context we should generally pretend that all people are created equal. But for most other purposes it is valuable to determine individual fitness for that purpose. And there are few purposes for which that fitness is uniform.
That's not all of Christianity. In the orthodox church for example, there's no hell even -- it's how a person perceives eternity without God, said distance from God based on their own predisposition (or tendency), out of their own free will. "Hell" in that sense is not some place, nor does it have actual fires and other BS folk iconography, it's a kind of regret:
> . . . those who find themselves in hell will be chastised by the scourge of love. How cruel and bitter this torment of love will be! For those who understand that they have sinned against love, undergo no greater suffering than those produced by the most fearful tortures. The sorrow which takes hold of the heart, which has sinned against love, is more piercing than any other pain. It is not right to say that the sinners in hell are deprived of the love of God . . . But love acts in two ways, as suffering of the reproved, and as joy in the blessed! (Saint Isaac of Syria, Mystic Treatises).
> According to the saints, the “fire” that will consume sinners at the coming of the Kingdom of God is the same “fire” that will shine with splendor in the saints. It is the “fire” of God’s love; the “fire” of God Himself who is Love. “For our God is a consuming fire” (Heb 12.29) who “dwells in unapproachable light” (1 Tim 6.16). For those who love God and who love all creation in Him, the “consuming fire” of God will be radiant bliss and unspeakable delight. For those who do not love God, and who do not love at all, this same “consuming fire” will be the cause of their “weeping” and their “gnashing of teeth.”
> Thus it is the Church’s spiritual teaching that God does not punish man by some material fire or physical torment. God simply reveals Himself in the risen Lord Jesus in such a glorious way that no man can fail to behold His glory. It is the presence of God’s splendid glory and love that is the scourge of those who reject its radiant power and light.
https://oca.org/orthodoxy/the-orthodox-faith/spirituality/th...
- U.S. Declaration of Independence
The above statement is false. That's more clear than ever and geno-economics contributes to that clarity. If you live your life by this assumption you will get many important things wrong.
Yet this clearly wrong statement, as applied to the operation of the rule of law, is also one of the most brilliant, important and useful concepts invented by civilization. As a proposition for how to engineer law to support a flourishing society, it is true and right.
I think that's the right way to deal with this controversy. Acknowledge that people have significant and important differences that are beyond their control, while also acknowledging that such difference can be overwhelmed by the effects of their nurturing and other controllable differences, such that it's better to judge them holistically and personally when that data is available.