So this is of course a proper hornet's nest but I am curious about one factor.
In Tolkien's cosmology, do Orcs have souls?
As in, are they complete, living beings, or are they just flesh machines?
In DnD, to the best of my knowledge, Orcs have souls. Orcs have Gods. Orcs are judged upon death for their actions.
I have never quite understood why Orcs need to be intrinsically evil in order to make fighting and even killing them OK. Killing enemy soldiers in war is generally seen as morally justifiable. If Orcs culturally view violence and aggression towards others as not only acceptable but morally correct, then resisting them would be just as just as standing against any number of conquering societies in human history. Were the Romans evil? How about Genghis Khan? How about Leopold II of Belgium?
What is at issue is that Orcs are coded with traditionally racist tropes. There are dozens of easily found articles and papers that lay this out. Big. Dark. Primitive. Uneducated. Driven to r*pe. Hell, it took until like 4th ed to remove that trope from 1/2 Orcs.
Short answer: I think you can make any people an enemy if you stress that what is at issue is that cultural norms that drive them put them into conflict with others. America was founded as a slave-owning nation. Most did not own slaves, and there were many who opposed the practice. But enough were either in favor or were at least neutral to the practice so that it remained with us until the Civil War. Were all those Americans evil? No. Did they live in a society that normalized a barbaric and objectively evil practice? Yes.