Let me say this about Diamond, and the conversation...
I have a feeling Wren and I have very similar experiences with works like Diamond's. In the context of very serious social scientific efforts on our parts - and those of many carefully interdisciplinary people we very much appreciate - to take material conditions seriously, we regularly run into wildly popular work like Diamond's (or Mark Reisner's Cadillac Desert or Garrett Hardin's/Paul Ehrlich's Tragedy of the Commons/Population Bomb) where the social is effectively obliterated - or at least made tertiary - by the determinate power of the material. The flip side of this, for me - and perhaps for Wren - lies in work like The Chalice and the Blade, where folks who take culture seriously watch the explosive popularity of a staggeringly vulgar determinism.
There are a number of reasons this drives me - and perhaps Wren - nuts. A little bit of it comes from watching - as you more or less put it - someone from the outside get famous saying unsophisticated and determinate things in large part by ignoring already existing and far more sophisticated and nuanced material. More of it comes from the relationship between our politics and our research. I, for example, was raised by neo-Malthusian conservationists and athletic preservationists but have a clear sense of the natural and social scientific failures of those research agendas and political programs. If, in fact, Diamond is correct then there is no viable political content associated with historical critiques of Western colonialism and imperialism - at least up to some unspecified point in history - because the technical, military, political, economic and, possibly, cultural superiority of Europeans was foreordained and predetermined by the climate and resources of that tiny continent. I don't have any problem with the idea that material phenomena have been very important to history but to treat them as determinate - and Diamond clearly is not committed to his wiggle words and caveats - is to deny contingency, agency and power.
Similarly, and given Wren's feminism I am pretty sure we're on the same page here, the history of the New Left is one where Progressive expertise came under intense scrutiny... for feminists this can be seen most clearly in the critiques of the foundational patriarchal assumptions embedded in most psychoanalysis, most family studies and most modern medicine... for environmentalists this can be seen in the critiques of the scientistic technophilia behind neo-Malthusianism efforts at population control and ecological conservation, bureaucratic expertise within the EPA and other agencies and the wide-ranging critiques of risk science within the environmental justice movement. The reification of science clearly undergirds Diamond's account and, perhaps, contributed to has refusal to engage with existing social/soft scientific studies of the very phenomena about which he wrote.
Diamond's work contributes to a politics which reduces to next-to-nothing critical social scientific and humanitarian studies of power and promotes the very mode of power/knowledge producing the material and social contradictions against which we struggle.
None of this is to deny the importance of the material, to reject technology (hello, Somebody) or to believe that we can proceed without science. It is to say that hypermaterialism, technophilia and scientific management are mutually reinforcing and tend to be very conservative and rather undemocratic.
Last, when someone asks for a list of alternative readings and then, when a list is provided, asks for what feels like a great deal more (because what was available on wikipedia didn't answer all questions), I think it not unreasonable feel trolled... however much the trolling may have been unintentional.