Natural Selection" - Selection by nature, not by humans. Given the theory is true, it should be that nature automatically mandates the survival of the fittest (intelligent people) and the extinction of the weak (the sheeps).
Aren't humans part of nature? While I agree that he doesn't quite grasp social-darwinism (which is a pretty idiotic concept and could just as well be used to justify capitalism, multiculturalism, consumerism, and stupidity), I don't think you quite have a grasp of it either. Nature isn't 'the other', it is the all. If you were to view nature (all of existence) as a single organism you would see that each plant, animal, mineral, gas, idea, etc is a cell or group of cells within that organism. The cells that are healthy or benign are cultivated while the cancerous ones are rejected. Social-Darwinism obviously isn't true since it seems the weak, parasitic, cancerous people have not been wiped out and often hold positions of authority. I think what Auvinen really believed was that humans have attempted to separate and protect themselves from nature and are thus allowing the cancer to grow.
Social-Darwinism, at least how it has been presented to me, assumes that the social realm applies the same selections to its constituency that the broader natural realm does. In reality, I think it's much more logical to say that societies form in order to manage and lessen the risks inherent in the chaotic, amoral, natural world. Religion, Morality, and Politics are all tools used in this process. To that effect, throughout history as societies become more and more complex they tend to disrupt the natural processes of nature yet essentially only prolonging their short stay before they are eventually engulfed by the chaotic force of nature.
This isn't to say that a healthy society can't exist. But that such equilibriums can be hard to gain and very easy to lose.