I won't dig into the issues I personally have with the idea of escapism and fun mixed with guiltlessly killing thinking, sapient beings
Boiled down to its most essential elements, D&D is a game centered around combat (i.e., violence and death). Sooner or later, thinking beings are going to meet their end by steel or spell...well, unless you're only slaying skeletons and oozes, anyhow. Surprisingly, you can indulge in a session of tabletop roleplaying where unabashed bad guys are getting killed while your character neglects/forgets to display remorse and not be a homicidal maniac in your everyday life. If one is incapable of keeping a barrier between reality and fantasy (e.g., they find it impossible to not view monsters as humans), that is an issue they need to address; the alternative is to abandon roleplaying.
Originally Posted by Gray Ghost
Because if adding nuance makes things boring and homogenous then the problem isn't the nuance itself, it's just bad writing and probably isn't actually nuanced. I fail to see how fleshing out a species that's traditionally labeled as monstrous and giving them depth and personalities could make them homogenous. I'd argue that the idea that "they're monsters because they're monsters" is even more likely to make things boring and homogenous.
Nup. Taking all the classic (evil) monsters* and essentially reframing them as misunderstood humans with fangs/green skin/bloodshot eyes/et cetera is boring. There's nothing wrong with throwing alien and completely inimical mindsets into the mix.
* Or the humanoid monsters, at the very least. Again, hardly anyone will lose sleep over the death of a young Chromatic dragon.