Ah yes, that comparison makes sense.
The prologue to Guns, Germs, and Steel outlines what Diamond sees as the most common explanations for the differences between peoples, and then uses the rest of the book to show why they are wrong and to offer a different explanation.
Probably the commonest explanation involves implicitly or explicitly assuming biological differences among peoples. In the centuries after A.D. 1500, as European explorers became aware of the wide differences among the world’s peoples in technology and political organization, they assumed that those differences arose from differences in innate ability. With the rise of Darwinian theory, explanations were recast in terms of natural selection and of evolutionary descent.
Today, segments of Western society publicly repudiate racism. Yet many (perhaps most!) Westerners continue to accept racist explanations privately or subconsciously. In Japan and many other countries, such explanations are still advanced publicly and without apology.
These explanations are still somewhat common today, and I believe that they were much more common in 1997 when the book was published. Even in the comments section on this post there is a suggestion that the Tasmanians’ technological regression was caused by biology—a population bottleneck causing inbreeding (I’m not saying that argument is the same as the ‘Darwinian’ one, just that it is also an explanation stemming from biological differences).
Guns, Germs, and Steel kicked off a genre of discussion that attempted to explain why Europe took over the world without assuming biological superiority. It seems like at the time, Diamond was explaining something new.
I did not intend to imply that historians were writing racist explanations for why Europe was able to colonize most of the world—sorry if that is how it came across! Instead, I believe those views were common among mainstream society. Part of that is because there had not been a cohesive, insightful, and popular alternate explanation.
McNeill is indeed one of the few historians who were investigating this question—and unfortunately I haven’t read any of his work. However, I don’t think that Jared Diamond was just repeating McNeill’s argument because the back of my copy of Guns, Germs, and Steel has this excerpt from a review that McNeill gave the book:
I dug up the full review online here. There’s certainly lots of criticism in the review—particularly of that epilogue. But also pay attention to how much McNeill praises Diamond for the new ideas he brings forward.
The tone of this review is radically different from those reddit threads. The modern online discourse about Diamond has amplified all of the criticisms from early reviews like McNeill’s, but entirely removed all of the praise. One of the reddit threads compared Diamond to a student faking a chemistry experiment—I certainly don’t think that McNeill had the same perspective! McNeill seems to have an honest disagreement with Diamond, he doesn’t think that he’s a fraud.
Reading those reddit threads can definitely make someone develop a heuristic “to not believe any analysis that Diamond presents, since there’s a significant probability that it’s misleading”. But I think that’s a shame, because Diamond has lots of unique, well-praised insights that are missing from the discussion in those threads.