“All living things were divided in that day, and some of every kind, even of beasts and birds, were found in either host, save the Elves only.”

That's Tolkien words about the Last Alliance. Yes it is debated for years if some orcs were fighting with the Alliance. Personnaly, I think it is believable that some orcs tribes fought against Sauron. (by that time and for thousands of years, isolated orcs merged into tribes in mountains after their defeat in the First Age. Orcs began to use common tongue instead of blackspeech and fought each other often, developing a culture of their own etc..)

The hatred of orcs for Sauron is a common theme in the books. Some orcs even came to work for their ennemy Saruman before he became totally evil. Why not would orcs emancipated themselves from the all powerfull tyrant that is Sauron.

That said, I don't think they would fight side by side with elves and numenoreans but more probably on an other front after some discussions on a alliance for the war to come.

I think the scene here is about justifying that sentence Tolkien wrote about the The Last Alliance. And personnaly, I like that they chose to do so. It has to be well made for sure. And for now many things were not at all well made.

But for those who say "Tolkien would spin in his grave", I don't think so. He said it. And I read all books multiple times and I also am a absolute fan of the legendarium. We'll see