"Inhuman" has strong connotations of inimical to human values-- your argument looks different if it starts with something like "game theory is a non-human-- it's a simplified version of some aspects of human behavior". In that case, altruism is non-human in the same sense.
I guess I'm mostly reacting to RAND and its ilk, having read the article about Schelling's book (which I intend to buy), and am thinking of market failures, as well.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.