I don't see what being copies has to do with being mindless. They are still intelligent, they would still diverge over time but they would learn and diverge around that same core personality.
I really can't understand how you're imagining consciousness to work. The core of it seems to be that all species are the fundamentally the same but all individuals are irreconcilably incongruous, and that thought is simultaneously deterministic and non-deterministic. But that doesn't make any sense to me.
EDIT:
Like, if somebody built an atom for atom replica of you, including the brain, we should expect it to be as much of a sentient being as you are, but also share your memories and personality, shouldn't we?
It is in effect a question of free-will, time, and world-building.
IF we assume that the original orcs were created by the gods to be evil, but that the orc's children could have drifted to be good or evil, then we have to look at how long that could have been.
Using FR as a base, just because they provide years, Orcs seemed to have come onto the scene 4,400 years ago (maybe later) and they were transplants, meaning they would have been even older. Orc biology seems to be twice as fast as human, so we are going to say a single generation would be 10 years.
That gives us 440 generations. To put into human context, that puts orcs as having since the time of Akkad and Sumer to change. Or, basically the entire length of human civilization. That is just too massive a time span for Orc culture to have never changed. Even elf and dwarf culture has changed in that time span.
And conversely one wouldn't expect a bird, a squid, and a pig to think and behave the same way, not even with training, so why should a human, an elf, and an orc all think and behave in the same manner?
And this argument falls apart when we look at how Orcs , Elves, Humans and Dwarves are presented. You'd be more accurate to compare Gorillas, Bonobos. Chimpanzees and Orangutans. To list just some of the similarities between the four DnD races.
All four live in large, social communities.
All four give live birth to children that they raise.
All four use tools, weapons, and armor.
All four domesticate animals for their use.
All four use language.
All four are bipedal with side-ears, front-facing eyes a nose and a mouth.
All four can use magic and have religion.
They have differences, sure, but the sheer number of similarities is very striking when you want to compare them to the animal kingdom.