Aldarc
Legend
There are a variety of factors at play. Are these creatures considered sentient? Are they extraplanar? To what extent are cultural analogues applied to them? Are there other problematic socio-cultural associations that may be at play that we need to unpack in these myths? Etc.But it goes back to a simple issue. If orcs are not necessarily evil, why are other monsters not necessarily evil? What about red dragons or chokers or beholders? After all they are just more stand-ins for the unknown, for monsters lurking in the dark.
Since the days of Arcana Evolved and Eberron (so around 2003 or so), my dragons have never been bound to a particular alignment. Beholders are extraplanar aberrations and frequently solitary, lacking cultural societies. They are utterly alien to mortals. Orcs on the other hand are mortal humanoids frequently defined in terms of their culture and collective society.
Overall, I think that you are grasping at false equivalences here so that you don't actually have to reevaluate whether your use of orcs feeds into racist tropes. Your rhetorical strategy seems to draw upon a slippery slope fallacy: i.e., "where's the line?" Because if we can't draw a line then you conveniently don't have to drop or think about whether you are perpetuating racist/colonialist tropes with your orcs.
But also if you make it so that every monster represents "stand-ins for the unknown" then it's somehow not a problem that orcs have a defined history of representing particularized colonial/racist caricatures and not just a vaguely defined "unknown monster." Not to mention the fact that trying to make everything problematic so that nothing is problematic seems like a warped reversal of values here.
And of course many people don't want to drop or reevaluate this because these portrayals and uses of orcs is psychologically safe, comforting, and fun for them. Many people like having your characters kill orcs without regret. And many people also like to think of themselves as a "good (non-racist) person." And if your chaotic evil orcs bring you psychological comfort were somehow feeding into racist tropes of evil "sub-humans," then you would probably be discomforted by the question "am I good a person for using orcs like this?" So how do you resolve the psychological discomfort? (1) You could address the problem by acknowledging the problem and altering how you use orcs, or (2) you can deny that the problem exists at all and resume your psychological comfort by trying to return to that blissful world of ignorance. And this latter strategy is how many people like going about their lives.