Well yes, biology shouldn't have any affect on what kind of person you are. Your intelligence, aptitudes, interests, gender role, or culture is not a factor of biology. The same is, in theory, true of other sapient beings.
So, stepping away from the hot argument, I'd like to add some nuance here. Because... maybe you're wrong, there.
We, in our real world, within our one sapient species in which race is a social construct with no biological basis, have had a horrible history with "separate, but equal", because in reality it was anything but equal. It is
absolutely okay to do away with that in our games.
However, it is also a hallmark of speculative fiction to ask, "What if?" Now, in our fantasy, real world biology doesn't hold - so terms like "genetics", "biology" and "species" do not necessarily hold either, but if we agree to allow for some flexibility there, we can consider what kind of impact "biology" can have on such things.
Are we actually sure that all sapience will be
completely separate from "biology"? Like, imagine a deciduous tree-people, who are dormant in the winter. Isn't that going to have impact on their collective culture? Imagine a "species" with drastic sexual dimorphism - if they are like, say, deep-sea angler-fish in which males are tiny with respect to the females. Is that not going to have an impact on their gender roles? Are we sure that all "species" have the same cognitive processes and therefore no differences in cognitive aptitudes?
Can we, for example, look at real-world dolphins, and think that, if they really are as sapient as they may seem, we should assume that their sapience is
exactly like ours? Or are they remarkably different?
Now, to be clear, I don't think that humans, elves, dwarves, and halflings are at all a good set of species to explore those questions. With the possible exception of elven extreme longevity, they are not obviously "biologically" dissimilar enough for such exploration. I don't think traditional D&D takes on these "species" have
interesting questions to ask with those differences - whether one is "biologically" drawn to ale is... not interesting, sorry.
But we could imagine using some other peoples for that purpose. Like, maybe dragonborn, lizardfolk, or tortles? Maybe tabaxi? Aaracora? Myconids or Ents?
The issue isn't that these questions can't or shouldn't be asked in our games - it is that so many use asking such questions
badly as an excuse for traditionalism.