So what? You're describing to me some supposed process of historical development, not how things "ought" to be. Is there some moral obligation for society to survive? How do you derive actual moral obligation from a mere description of animal behavior conditioned by the environment for survival? All Darwin gave you was a descriptive account of environmental selection of certain behaviors that tend to conserve species, which tells you nothing about why things ought to be that way.
With a sympathetic society the whole is truly greater than the sum of its parts, not so with an unsympathetic one. Darwin makes the perfect argument against eugenics.
Why should anybody feel obligated to obey a blind, impersonal evolutionary force? And how can a physical force or power or an effect of physical forces, such as natural selection, be "sympathetic"? Is there some material force of nature that obligates a whole to be greater than the sum of it's parts? The insurrmountable problem you will continually run up against is that you cannot derive an "ought" merely from what is, by reason alone. Darwinism does not make any argument against eugenics at all because if it is taken to its logical conclusion it eviscerates any foundation for morality.
Now you're arguing the validity of his views, which isn't the subject.
How do you derive actual moral obligation from a mere description of animal behavior conditioned by the environment for survival?
These were observations of what makes a human society powerful vs. simple genetics. Darwin was showing how his theory of physical natural selection at animal level does not apply to human society, yet those in favor of eugenics ignored him, and still his enemies blame him for the views of the eugenicists.
Darwinism does not make any argument against eugenics at all because if it is taken to its logical conclusion it eviscerates any foundation for morality.
You are again changing the subject to the origin of morality. In this sense what makes for a sympathetic society, a society that will be stronger and longer-lasting than those around it, is the foundation of morality. These rules were later written into various religions as absolute morality.
I don't suppose you've noticed that Christians, who have one of the best sets of moral laws in the world, dominate this world. Muslims are a freak, as they dwindled into irrelevancy, their societies dying out, until it turned out the horrid places they settled (the places the stronger societies didn't want anyway for the most part) were rich in valuable natural resources. That accident of geography upset the natural order according to Darwin, which is that unsympathetic societies will die out.
Couple that with many Christian societies becoming quite unsympathetic, as you see with the prevalence of abortion, not taking care of our elderly, etc., and you see how Christian power has declined.