The first half of that deals just with a strawman. I don’t say climate’s the only factor. On the contrary, I say explicitly that there are always, with every single social phenomenon, many causal factors. So cold climate needn’t be the only way to generate favourable social outcomes. Thus, those examples of countries in hot regions that have favourable aspects to their society are perfectly consistent with the hypothesis. They’re not counterexamples.
Saudi Arabia, for example, would be able to impose its social safety net because that sort of long-term planning is one of the benefits of a dictatorship. That system comes with costs, too, such as the lack of certain human rights. Obviously, the societal default of autocracy must have its benefits, or this system wouldn’t have been used so extensively in history.
The question, though, is whether the social safety net in Saudi Arabia is due to rationally enlightened planning, to the sort you’d expect from high levels of cognition, assuming those levels are easier to maintain collectively and in the long run in a colder climate (as per the hypothesis). And that’s not so clear. The lack of public trust in a dictatorship is obvious from the fact that dictatorships hold on to their power by oppressing the population, not because the people genuinely respect and appreciate them. Is the social safety net in Saudi Arabia great enough to make up for the lack of human rights, such that the public wouldn’t rebel against the government if it had a chance? I doubt it.
But sure, illiberal countries can have social safety nets because social phenomena always have multiple causes, so that there’s always more than one way to get from here to there. That says nothing about whether climate is one such causal factor, meaning that climatic differences help explain the geographical distribution of political systems.
As for the second half of your comment, I don’t think racism is so relevant. Nordic countries are still large enough that they’re not mere tribes, meaning that even if most Norwegians, say, look similar, they’re still mostly strangers to each other. What you’re saying there would apply more to prehistoric tribes of hunter gatherers (maxing out at around 125 members), not to large societies that call for more than just our primitive social instincts to keep the peace. We rely on myths and on the rest of culture to maintain social stability in these highly artificial settings, so the instinct to favour a certain race won’t be sufficient.
Nordic peoples are bound to trust their system not because they’re biologically programmed to be racist, but because their system obviously works, as indicated by all the rankings I cited, and because that system seems fair to secular humanists, the latter philosophy being the result of higher levels of cognition (as opposed to the Islamist fundamentalism you see in Saudi Arabia).
Moreover, the US wasn’t always racially diverse (although it’s still mostly “White,” by the way). Yet the Civil War indicated a cultural divide before mass non-European immigration to the US. And look at a map of the two sides of that early conflict: it was the north versus the south.
https://en.wikipedia.org/wiki/Slave_states_and_free_states#/media/File:US_SlaveFree1858.gif
