This is a good thoughtful article, and interesting enough that I will be reading more of the author's blog posts. But I think they're slightly misunderstanding some of the material they discuss.

Diamond’s stated intention is to do away with the racial superiority explanation of the difference in the current power arrangements. And he explains a part of it. But he is not careful enough to explore the boundaries of his model. And when applied at the right level, his model does what it sets out to do. But when applied at other levels of magnification, it does exactly the opposite. It provides a way of justifying real bad human behavior as inevitable.

This is perhaps most starkly exemplified in his description of the Rwandan genocide in his other book ‘Collapse’. There he recasts it in terms of simple competition for resources. He may be right. But as recent Timothy Synder’s book on the holocaust argues, that same was true for the Nazi genocide (in the idea of lebensraum). But those were not causes. This involved people like us shooting other people like us. Up close and personal. And other people telling them to do it and benefiting from it in many ways.

I wholly agree with the author that people have moral responsibility for their behavior. You can find examples from the Spanish conquest of America, say, where contemporary figures were saying 'this is bad actually, we ought not to be sponsoring or endorsing this at all.'

But what I think has been overlooked is that having the right technology (such as guns) or natural advantages (immunity to some pathogens) often provides such a huge asymmetric advantage that a small number of actors can achieve strategic dominance in a short time frame, and set off a cascade of events that allows them to lock in those gains permanently (or at least over centuries, which is the same thing from an individual perspective). This can happen even if the small group are outside the moral mainstream and acting in a way that would get them condemned in their originating context.

Now, it's quite true that people who are activated by resource mobilization are not motivated by moral causes but by plain self-interest. Indeed, very often they construct an alternative moral myth in which they assert that they Had No Other Choice and so did horrible things out of necessity. These myths are often untruthful and may not even be believed by the proponents (although they will happily employ people who do believe them as instruments), but once people have adopted a necessity argument they're signaling the termination of their susceptibility to moral reasoning.

Thus, while it's good to point out that Great Figures in History were often amoral or immoral assholes, it's facile to think that pointing out moral problems is sufficient to prevent future abuses. Where large asymmetries of information and/or force exist, someone will try to exploit them sooner rather than later, and if hey do so successfully the resulting strategic gains can often be rapidly compounded. In such contexts, protesting the immorality isn't effective once the exploitation is underway; you have to either outwit or outfight them. It's not the moral hand-wringers are wrong; it's that they are powerless.

This is the core problem with nonviolence as a political/social/moral theory: it only works to the extent that everyone feels constrained by it. Deploying nonviolence against someone with a demonstrated willingness and confidence to use violence is self-defeating (they literally don't care what everyone else thinks), and advocating it is irresponsible (because once it's clear that it's not going to work, it's just going to lead to people getting hurt and probably improving the strategic position of the violent antagonist who benefits by injuring or killing their opponents while incurring no painful costs of their own).

In sum, nonviolent moral suasion is a Good Thing and should be the default approach, but if you try it and discover that it's not working then you should change your tactics or you'll get crushed. Retrospective vindication is absolutely not guarantee against the same thing happening in future, because sooner or later a new technology will come along that give rise to great asymmetries, and the larger the asymmetries it yields the more likely it is that some bad actor will exploit them.