I think you're reading their phrasing in an ungenerous way. Please consider the Hacker News guideline: "Please respond to the strongest plausible interpretation

I think you're reading their phrasing in an ungenerous way. Please consider the Hacker News guideline: "Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith." The article authors lead a paragraph by saying "most societies", but they go on to characterize what they mean with greater specificity and provide citations to further research on the topic: > Several societies have seen as little as 1% of their population own approximately 50% of the total wealth. This was the case in many Western countries around 1900, including Britain, France, and Sweden, and some claim that at present, roughly 1% of the population owns 50% of total wealth at the global level (1, 2). > We focus on wealth and not income distribution, which is much less unequal and—perhaps surprisingly—poorly correlated with wealth inequalities across countries (SI Appendix, section 2). As a first illustration of the similarities of patterns in nature and society, consider the wealth distribution of the world’s richest individuals compared with the abundance distribution of the Amazon’s most common trees (Fig. 1 A and B). The patterns are almost indistinguishable from one another. > For a more systematic comparison, we also analyzed the Gini indices of a wide range of natural communities and societies (Fig. 1 C and D) [emphasis mine]. The Gini index is an indicator of inequality that ranges from 0 for entirely equal distributions to 1 for the most unequal situation. [...] Surprisingly, Gini indices for our natural communities are quite similar to the Gini indices for wealth distributions of 181 countries (data sources listed in SI Appendix, section 1). If you want to critique their argument, please consider examining the societies that they included in the analysis described above. They appear to be examining societies that are countries, probably because economic data is available aggregated at the country level.