The question is, are you ok with other people not following your line of reasoning, and just making traditional worlds with races like Tolkien's orcs? Would you play in a game like that, and if you wouldn't, would you just leave or encourage others to follow your example? This game is played at a table, physical or virtual, with other people, and making that experience fun for that particular table is the only goal that really matters. Imo.
If the DM chose to do that stuff and was openly and explicitly cavalier about the unpleasant implications? Yes, I would leave, and I would in no uncertain terms recommend that everyone else do as well. I would speak up (and, as I think this thread has shown, have done so) to advocate against it to others.
A DM that actually cares about the implications and addresses them, as Oofta has, is doing a very good thing. Regardless of our disagreements on a great many topics, I genuinely respect them for that choice.
So, what if you remove the coding? What about having orcs, having come from elves, look the same as elves - conventionally beautiful, ethereal, etc., other than often being built like linebackers? But still evil?
There are other issues, as I mentioned earlier. First, as Professor Murder noted, racial essentialism. Second, I don't see how you can have the two sides of this. A being that is morally culpable (capable of being
responsible for its morally-evil actions, warranting censure or punishment for said actions), and yet incapable of actually making any choices other than evil ones. A being that has an individual personality, but which is completely devoid of free will. Etc. It sounds like having your cake and eating it too, or rather having your cake and also never baking it.
So, while this would dodge the really nasty issues attached to the problem, it would still leave the "okay so...how can they be
blame-worthy (evil) if they
cannot make choices?" And if they CAN make choices, how is it they can be
truly always evil?
Hence why I did what I did with my fiends. There's a
reason they wouldn't choose good. If it had been possible to persuade them before, they would have
eventually been persuaded in their infinitely-long war. It takes a truly "outside context" situation to change a demon or devil's mind. They
could choose differently...but they have been so committed to evil for so long, such choices on anything remotely like a human lifespan are essentially guaranteed to never happen.
And both demons and devils can
choose to look beautiful if they wish. Many don't because they value the fear factor, but some do (succubi/incubi, for example, have an innate "voluptuous field" effect, walking pinups whose clothing clings to the body in unnaturally beautifying ways.)
But in the example I'm giving - there are no physical or genetic differences. They are still one race. Just some are randomly born innately evil, and some aren't.
Well...if they're literally identical to elves, some are Just Evil and others aren't...is that actually an "always evil" race? Because it doesn't sound like that.
It would still seem to run afoul of the "how can they make free choices and yet also be incapable of making good choices,
while still being morally responsible for those evil choices they literally cannot avoid?" problem.