I completely agree, particularly about the parental investment thing. If the supposed goal is to spread your seed far and wide, but also to ensure that such seed grows and has evolutionary success (lives to have it's own children) then why do so many men abandon their offspring? These same folks also believe that a man would never want to invest in raising another man's child - and yet, that happens routinely all over the world - quite often by design as with partible paternity.

This quote from primatologist Frans de Waal makes the most sense to me about how patriarchal notions of social organization aren't the story of most of human evolution: "When group stability is important for individual advantage, selection will favor active peacemaking and cooperation in our closest relatives and ourselves."