You're doing it too, and have been throughout. Where does thing requirement for something to be 'innate' (whatever that is) come into it? It doesn't, surely?
It comes into it in the broader concept of social justice and acceptance, as well as medical treatment.
Let's step a bit sideways, knowing that this is purposefully leaning toward an absurd example. But I think it might help illustrate why nature versus nurture comes into this discussion.
Let's talk about race. Specifically about black and white Americans. There's a measurable difference in outcomes on the basis of race in the US. And there's a substantial amount of evidence for differences in the lived experience within society of black people compared to white people. There are significant differences in how people are treated, how they are perceived to be likely to act, and what is expected of them on the basis of skin color. It's a thing, and nobody thinks it's not a thing.
Historically, people believed that the differences were natural. That black people were just by nature, inferior. They were believed to be less intelligent, less capable, and more aggressive and violent. That belief presents a very real social barrier to black people in the US. But there hasn't been any solid evidence to support the argument that there is an inherent, innate, natural difference between black people and white people that sufficiently explains the observed differences in experience and outcomes.
Now, however, there's been an upsurge in people who identify as transracial. They are white people (sometimes mixed people) who identify as black. There are also some black (or mixed) people who identify as white. For the most part, it doesn't make any difference, nobody cares what race you identify as. Dress however you want, hang out with whoever you want, etc. Surround yourself with people that you resonate with and feel comfortable with. But, because there has been such a well-documented history of disparity on the basis of race, there are also some social systems in place that are aimed at addressing that issue and providing a more equitable experience to black people. And to the extent that a person may claim they are transblack, there is an expectation that they would have access to scholarships and educational grants set up for black students. There's an expectation that they would fulfill a company's affirmative action requirements for diversity by being classified as black. For people who are mixed, or who are "dark enough", there's a fair bit of acceptance, and not a lot of push-back. For people who look like a comic-book version of a Swede, however, there's a bit more skepticism.
Now, into this hot-bed of mixed objectives and potential conflicts of objectives... someone comes along and says that there are differences in the brains of black people and white people, and that transracial people's brains are closer, in some few aspects, to the brains of the race their identify with than to the race they were assigned at birth.
Because of the impact of this on black people as well as transracial people, the question of causality does become fairly important. If there is an innate root cause - something in the brain of that transracial person that definitively supports their identity as black, then that ends up meaning that there's a real and material difference in the brains of black people compared to white people
that is not the result of their lived experience and conditioning. There's also, however, a whole lot of risk that such differences, no matter how immaterial to outcomes, could be used to
justify and rationalize the continuance of disparate treatment on the basis of race. On the other hand, if those differences are not innate, but are the result of external exposures and brain plasiticity, then that jeopardizes the strides that transracial people are making toward their own recognition and acceptance.
The question of nature or nurture (or both and to what extent), then, ends up being a fairly important question for both black people and for transracial people... and there's opportunity for antagonists to abuse that information on either side.
For most reasonable and well-intentioned people, it's not a big deal one way or the other, because we treat people with respect and dignity regardless of their race or gender or what color socks they wear. We care about behavior and actions, and we're simply not judgy about people's personal lives. But not everyone is a reasonable well-intentioned person, and even if it's a relatively small number of people, misogynists do actually exist. And sadly, there also exit a very few transgender people who are bad actors across the board. No answer is going to make everyone happy, every solution has the potential to dislocate someone, and every solution opens the door to some abusers of that solution.