blue trane's Journal: Altruism, kin selection

From _The Genetics of Populations_, by Jay L. Lush (1948), quoted in _The Altruism Equation_ by Lee Alan Dugatkin, page 165:

The competition and selection between families ... could make selection favor any genes which tend to cause the possessor to sacrifice himself ... provided the sacrifice promotes the biolgocial welfare of his relatives (some of whom will have some of the genes he has) enough to more than compensate for the genes lost in the self-sacrifice. ... The balance here is intricate, depending on how extreme the self-sacrifice, at what stage in the life-cycle it occurs, how much this increases the biological success of the benefactor's relatives, how closely related they are, etc. The balance depends primarily on whether the greater biological success of the relatives will multiply the genes for altruism more than enough to compensate for the loss of those genes in the individual which sacrificed itself.

How does the mathematical theory of altruism (formalised in Hamilton's rule as rB > C) predict open source, where the degree of relatedness between those who produce and those who benefit is unknown and irrelevant? Does Hamilton's rule account for the existence of the World Wide Web, food stamps, of food banks, of non-profits, of the Southern Poverty Law Center, of the Civil War, etc.? It seems that there are studies that provide supporting evidence for Hamilton's rule; but there is also a lot of behavior that we see around us everyday that doesn't support it. Another example, people helping each other on irc, answering questions, etc. There are also counterexamples to Hamilton's rule: sibling rivalry (Cain and Abel), fratricide, infanticide, etc. Why aren't these observations mentioned when discussing Hamilton's rule?