I believe it's because in many cases, the unspoken follow on to "inequality is the norm" is "and so it's useless (or actively harmful) to try to defy that norm."

Not that above commentator is meaning that.

But many "thought leaders" i.e. Jordan Petersen play around with similar motte-and-bailey - "hierarchies are natural" (examples with lobsters, apes, whatever) --> "existing hierarchies should be preserved" (not defended in the argument but implied).

Probably some downvoters are reacting to the structural similarity, although taken in good faith i think above commenter makes a fine point about the historical pattern of periods of equality being short lived and brought about by great intentional effort while sliding back to inequality seems to occur all of the time.

We do need to include the vast human pre-history when makings sweeping claims about the natural state of human society. There might be something about civilizations that concentrate power which wasn't seen nearly as much among hunter-gatherer groups. If so, there might be steps that can be taken to counter it (indeed the past several centuries would strongly suggest so).