Because when you become aware that an injustice exists you should consciously try to do something about it? One of the easiest ways to do something about it is by buying and supporting work by female authors.
And of course a writer's identity will play a role in the work that they produce. No one is writing Toni Morrison besides Toni Morrison, and a Fanon essay is a Fanon essay because he experienced being black in France and Algeria.
I'm sorry, I don't buy books to solve injustice. I buy them to be informed or entertained.
Why stop at choosing books by gender? If it's irrelevant to the subject matter being written on, should I buy books based on someone's nationality? Their religion? Their race? Their sexual orientation?
Citing examples of authors where the subject matter is relevant to their identity is not a counter-argument to the point I'm making. I'm in agreement that only Toni Morrison can write about Toni Morrison's identity-related experiences and only Fanon can write about Fanon's identity-related experiences. However, if Fanon and Toni were to both write a book on something like the 2008 banking crisis, I would expect the their lived identity-related experiences to be largely irrelevant to the final product each produces.
This reduction of individuals to their identity is dehumanizing.
You don't think a person of color writing about the subprime mortgage crisis would write a different book than a white banker that worked at Bear Stearns? A crisis in which black and Latino applicants were almost 2.5 times more likely to be given a subprime rate in comparison to white applicants? [1]
No one is reducing individuals to their race or gender identity, but unless we're talking about pure science and mathematics books it is a show of ignorance to argue that lived experience has no bearing on the work of the author.
The inherent racism in your example notwithstanding, the two examples you chose aren't even comparable. You didn't say "a person of color" and "a white person". You said "a person of color" and a "white banker that worked at Bear Sterns". That's pure apples and oranges.
The relevant lived experience is being a banker at Bear Stearns, not the race of that banker. Also, how do I know the person of color isn't also a banker at Bear Sterns. I worked in Wall Street years ago, and yes, I had co-workers that were people of color.
And of course a writer's identity will play a role in the work that they produce. No one is writing Toni Morrison besides Toni Morrison, and a Fanon essay is a Fanon essay because he experienced being black in France and Algeria.