Should be noted there is a massive difference between racial essentialism and bioessentialism, and that even bioessentialism isn't inherently negative.
The negative traits with these ideas are rooted using race or biology as a way to deny agency to certain groups, including for that matter cis white males (though in a different way than it is for literally everyone else), and instead frame their behaviors and outcomes in life as something out of their hands. That creates a rather distorted view of how humans actually behave and why.
The question of bio or racial essentialism, however, becomes incredibly muddy when you start to talk about fantasy worlds.
To start, in the vast majority of fantasy worlds, race as we use it in real life is a false equivalence with how race is used in fantasy. The latter is typically more appropriate to call species, though there's a lot of names you could use instead.
So right off the bat, trying to invoke racial essentialism in a fantasy world is ridiculous.
That aside, bioessentialism is applicable to fantasy worlds, and this is where it gets muddy.
For one, even in real life humans, earlier Human species did have different cielings and floors from us in terms of physical and mental capability, and while we're continually finding evidence that many of them were closer to us than we previously thought, many of them weren't and unless we make some pretty shocking discoveries to the contrary, they most likely couldn't ever have been.
For two, in fantasy worlds even if one assumes a given species evolves to have a similar capacity to do these things as to humans, ie such as having vocal coords and an ability to share languages, the fact that they are fundamentally different species is going to have exponential effects on how they behave at an instinctual level, and how their culture develops over time.
Bird people in isolation aren't going to be anything like humans, even with similar capabilities, and what similarities will be there will likely be true of any species that reaches this stage of development. After all, within humans you can see the same phenomenon with isolated populations. They're still just as human, but culturally they only resemble whatever group they split off from thousands of years prior, and are now unique.
But, species most likely wouldn't live in isolation. Bird people and cat people and humans all living together and having intertwined histories is going to change how all three of them develop.
Not only will the bird and cat people be closer to humans on that basis, the humans themselves aren't going to be as close to us in real life as they usually are depicted as a result. Trying to anchor fantasy humans as always being us is a big worldbuilding issue and has a lot to do with why these issues crop up. (Most aren't going to be making allegories when even the humans, if they're even called that, are fantastical)
And thats all just if we're assuming a world that developed all these species through evolution.
Most fantasy worlds, within their own universes, are intelligently created, and so too are the species that inhabit them.
At this point you can't really claim bioessentialism to be a strict negative, because a god who creates an entire species out of whatever is clearly going to be able to dictate everything about them.
One might find it interesting to explore if said god exists but doesn't have that power specifically, but that isn't what fantasy worlds have done and certainly isn't what the world we're all thinking of does.
So as much as one may not like the trope that all Orcs or Dark Elves are evil, in the context of most fantasy worlds, its not a question of essentialism, a philosophy applied to deny agency to minority groups and even to their oppressors.
Its cold hard fact. Gorignak the Defiler birthed the entire race of Orcs and by his decree they know only violence, malice, and contempt.
The actual issue with this trope isn't some essentialism malarkey, its actually that its just a shallow trope that doesn't leave a lot of room to tell stories with.
The one Orc who defied Gorignak and becomes a hero instead is a compelling story. That you can realistically only tell once.
Hell, in a way, LOTR only got away with this because it told the Hobbit over again four different ways in four different contexts simultaneously. A very difficult feat to pull off in a funny elf game where the tropes are far more obvious and deliberately invoked.