That's what I thought as well, but now I don't think that is what they are arguing.
@Haldrik, correct me if I'm wrong . . .
If I understand
@Haldrik correctly, they feel that in the D&D game right now, the game does not distinguish between
inherited traits (species) and
learned traits (culture). Some folks are fine with that, but would like more choice and granularity in selecting racial traits for their character.
I agree the game does not make that distinction currently, and for those of us who would like to separate
inherited traits from
learned traits, deciding which traits are which is something we can argue about, as I did in my above post about elven adaptations potentially being described as
inherited or
learned, that either could work.
Personally, I see the current D&D racial traits as a mix of
inherited traits and
learned traits. I would like to see a system that separates them and makes that distinction. I've seen some good designs towards this, I really like Arcanist Press'
Ancestry and Culture.
(Haldrik is "he".

)
Several concerns are going on at the same time.
• Reallife concerns to avoid systemic racism. Coming from an earlier era, D&D intentionally used racist terminology and concepts, including the word "race". Note, D&D has always defined "human" as a single race. Other races were strictly nonhuman. At least dejure, if not defacto.
• There is strong desire for D&D to abandon the term "race", to distance the game from reallife racism.
• To replace the word "race", there is debate about what the new term should be: "species", "heritage", "ethnicity", "folk", "ancestry", etcetera.
• The possibility of "species", motivates some to distinguish between "species" (nature) versus "culture" (nurture). Thus there is a new effort to distinguish between traits that are obviously learned from "culture", such as Elf with longsword weapon proficiency, versus traits that seem more biological that seem to come from being a "species", such as, Darkvision.
• Since D&D "races" are racist (essentialist thus quasi-biological), D&D never distinguished between nature versus nurture when describing a race.
• But now with a hypothetical "species" contrasting "culture", can the traits of the former race be reorganized into these two hypothetical categories? And the answer is, no.
• Even Darkvision is magical − not biological. Its ability to see in total darkness, is magic. There is a spell, called Darkvision. Someone learns the spell, and casts it. A spell like Permanency, or Wish, can make this magical ability permanent, and even inheritable. Thus the origin of Darkvision is strictly "culture", and cant be biological.
• What is true for Darkvision is true for any biological trait: Size, gills, wings. Officially, elven cultures shapeshifted magically to adapt to new environments. The biological changes are by means of cultural choices.
• So, it seems, D&D was right all along to just lump everything together into one pot.
• Which now, ironically, turns out to be a good thing! Originally D&D did it because everything is biological ( = racism!). But, because magic, everything is actually cultural. In other words, everything is because of learning magic and exercising ones own freewill personal choice ( ≠ racism!).
• So maybe "species" is a less useful term in D&D, to describe any Humanoid who can learn to wield magic to transform magically, by choice.
• Perhaps a word like "heritage" is more accurate − in the context of magic. Because an individual "inherits" their current form that they were born into. However, the person can freely choose to cherry-pick what parts of this "heritage" are useful, and what parts are less useful, now, today. Today, a person can choose to shapeshift the less useful parts, to update the heritage for future generations.