There is an argument that hierarchy and inequality are a reflection of human nature, not the result of unjust social arrangements.
If we are to address this question of a human nature objectively, then we will have to agree that determining our nature requires looking at the history and prehistory of the species scientifically and historically. As a distinct species, Homo sapiens has been around, in its modern form, for at least 200,000 years. The species originated in Africa and migrated outward, reaching nearly every part of the world by roughly 25-35 thousand years before present. Some 6-10 thousand years ago some groups of Homo sapiens began living in large-scale social systems in the Indus, Nile, Tigris-Euphrates, and Yangtze River valleys. Meanwhile, most members of the species continued to live outside the city-state environment for thousands of more years, finally being incorporated (with a few notable exceptions) into modern world-system by the mid-twentieth century.
It is with the emergence of the city-states that we see the regular appearance of the major forms of social segmentation, i.e. class, gender, and ethnic divisions, unjust arrangements which, over time, required, among other things, an ideology claiming that selfishness is part of human nature, which in turn, it was said, explained such things as exploitation, genocide, property, war, and so on (as if these are simply the natural conditions of human existence). However, before the city-state and outside it, human beings for the most part lived in democratic egalitarian social orders, communities based on cooperation, sharing, and compassion. In essence, these societies were based on altruistic relations and behaviors, not on selfish ones.
Let’s do the math: Taking the more generous number of 10,000 years ago to establish the emergence of the selfish conception of human nature, and the conservative number of 200,000 years for the existence of the species (it’s probably longer, and moreover we have earlier hominids displaying symbolic culture who also enjoyed communal existence going back more than a million years), we find, measured temporally, that 95 percent of human beings lived in communist and socialist societies in which either everybody owned everything in common or those who worked kept what they earned for their families (which were extended and essentially covered, through larger familial networks, the entire community). In other words, at best, only 5 percent of human beings have lived in the types of social orders that the advocates of selfishness (and exploitation and inequality) seek to legitimize with their appeal to human nature.
Judging the matter using archeological, anthropological, historical, and sociological facts and analyses, we would have to conclude, from a human nature standpoint, that class-based societies are contrary to human nature, not a reflection of it.