LOTR goes into enough detail about Orc society about as much as knowing the tax policy of Aragorn as King of Gondor.

But even then, this analogy falls apart immediately. The uruk-hai were designer soldiers that were the best troops in the army because, you know, they were designed to be the best class of troops.

I do not know of any details in LOTR that goes into the promotion policies of the officers of Sarumans military.

Insofar as there is any hierarchy in among the orcs, it must have come from certain individuals showing themselves to be more capable, brutal, commandeering, or whatever else, than others.

I have not read LOTR and got about 10 pages into the Silmarillion before giving up, but my understanding is that Tolkien designed his world meticulously. If he didn't go into detail on this matter I have to assume that it was for a purpose, possibly either of avoiding unfortunate implications by comparison or of enhancing the dehumanized characterization of the, er, foreign hordes.

Outside of the fandom, LOTR is commonly understood to be problematic in its treatment of "race" and social structure, at least wrt contemporary society and its necessities for peace, order, and dignity. I don't know that this is a controversial take at all.

I do not remember anything that would indicate that orcs selected leaders or anything else based on merit.

Parts that were shown included plenty of violence, treachery, oppression including slavery and other mistreatment (all included also orcs as victims).

With basically no reward for merit.

> All the good-guy societies are deeply hierarchical.

Yes, but the same is true for evil ones.

And if anything, good guys have less extreme hierarchies. Especially hobbits.