I will let the reader judge who is missing whose point, My point, reiterated in every post here, is that what you call morality is not morality at all, but merely descriptive accounts of environmental selection of certain behaviors that tend to conserve species, which tells you nothing about why things ought to be that way. Morality is about "ought", not about what merely "is". You also can't by reason alone derive ethical principle from a mere fact of nature.
You can't appeal to "higher tendencies" without justifying the leap because under a naturalistic Darwinian premise matter in motion is all you have to work with; concatenations of atoms and molecules are not directed or purposeful, and the "higher tendencies" is what you being asked to account for in the first place. You are limited by your premise to thouroughly naturalistic explanations based on material causes.
But the context here is an attack on Darwin because of what the eugenicists believe. I think you've about admitted such attacks are unfair without realizing it.
No, here I simply accepted your premise for the sake of argument, not because I think it is entirely factual. My point is that Darwin had no foundation for any of his ethical judgments. By all accounts Darwin was personally a kindly man, but his naturalism destroys any possibility of a coherent account of morality.
.Does religion give such an obligation?
If you regard religion as man-made, i.e., having emerged along with man from the primordial slime, then no. In that case it would be just as arbitrary and subjective as your utilitarian ethic.
We are playing dictionary games. Call it what you want, but morality is a reflection of that.
You are limited by your premise to thouroughly naturalistic explanations based on material causes.
The causes are how we interact socially.
No, here I simply accepted your premise for the sake of argument, not because I think it is entirely factual. My point is that Darwin had no foundation for any of his ethical judgments.
The naturalistic view was his foundation. It is the same foundation that religious ethics and morality is built upon, although religions don't like to credit the source.
In that case it would be just as arbitrary and subjective as your utilitarian ethic.
It is arbitrary and subjective. Long ago some people founded a religion, including in it the societal mores of the time. They later wrote these mores as laws into the religion's founding documents. That is your arbitrary and subjective starting point.
Notice how the Bible doesn't condemn slavery? That's because slavery was normal and accepted in the society of the time. I don't think slavery is moral or ethical, but that's because I live in a post-slavery society. You do have the rare person who comes along and introduces new ideas on how society could function better than it did before, and they'll be accepted and perpetuated if they actually work in society. Jesus had some great ideas, and that's why Christianity lasted and prospered. Hitler had some ideas on how to make society better, but they didn't last very long. In fact, the more sympathetic societies smacked him down quite hard. Stalin and Lenin had some ideas too, and the USSR is gone while we're still here.