You're giving these people
way too much intellectual credit. Here's the reasoning:
- The protagonists are white Europeans.
- The orcs are described as evil, nasty, brutish and corrupted.
- The orcs are fighting the white European protagonists.
- Because of that antagonistic relationship the orcs must be coded black.
Of course, that's ignoring the corrupted
humans under Sauron's command that Tolkien actually described as having dark skin, the Haradrim (or the people of the south). They're the elephant-riding tribal folks you see in the Battle of the Pelennor Fields in the movies. In the movies they got whitewashed a bit into a light brown but in the novels they're described as having "swarthy" complexions, IIRC. It's actually one of the "problematic" things people see in the Lord of the Rings books.
That's also ignoring the orcs' description as
"squat, broad, flat-nosed, sallow-skinned, bow-legged, with wide mouths and slant eyes, long arms, dark skin, and fangs". They're essentially large goblins by modern standards. But that would make them really hard to cast and costume human extras for them.