Is it?
I dont think so.

I think its easier to write a heroic narrative that way. Its easier to bring analgoies to the table iwthout having to revolve the entire cmapaign around it. Is that neccesarily a bad thing? I dont think so. Much like Sci fi, fatnasy is in the universe of "what ifs".
That includes objective morality. Which in turn gives you some rather unique storytelling potentials that modern fantasy writers sadly seem to forget about.

The idea that Orcs are just walking XP is somehow sitll thrown around despite beeing wrong for 3 editions now. I mean it all started out with spelljammer and the Scro, but even "Evil" orcs have plenty of nuance now.
Mindflayers are the next thing. They are Evil,c apital E. Theres no of that moral "nuance" there, but you dont need to.

Imagine Mind flayers were not evil. Would that improve the stories you can tell with mindflayers?
or would it actually detract from their terror?



But here comes the most important point:

One has to realize that the non Human races of DnD arent supposed to represent Humans.
If you want a complex war with another nation, you discribe Humans fighting Humans.

If you want to use a Humanoid enemy you can fight with weapons to symbolize a terrifying external threat. You use orcs.


For some reason Game of Thrones is ofthen cited as an example of fantasy dealing with "grey moraliy", when thats complete nonsense. But game of tThrones is a great example of how to use "always chaotic evil".
The white walker sin game of thrones ar ethat. Enemy of all life.

Does that make them lazy?
Or racist?
No. They are an analogy. The white walkers are an analogy for Climate Change.
The Threat of the white walkers is there to make a point about the Human rulers not working together and not beeing able to face the threat.

Only fighting Climate change with Swords and arrows makes for a supremeley better book than fighting it with lessening carbon emissions.


Do you understand where im getting here?
The Orcs are Evil because the Orcs do not represent Humans. The Orcs represent a savage existential threat and the fear of Savagery overcoming civility in Human minds.
They are the shadow on the wall of the primeval cave. Not neccesarily orcs but all kinds of Eivl creatures.