This is an interesting question. Epistemology is certainly identitarian. For instance, Judith Butler explains in her book "Frames of War" that "Frames" ( things that organize auditory and visual experiences - research papers, television, film, novels, etc.) literally generate ontologies (social categories and social norms).
Frames produce intelligibility. Which she defines intelligibility "as the general historical schema or schemas that establish domains of the knowable."
The dominant "Frame" in various social fields (colleges, Judicial, public education, congressional professions, CEOs of Fortune 500 companies, law enforcement, etc.) are gazes that are necessarily limited by the experiences, metaphysics, etc. of the people who predominate these fields (heteronormative, maled, whitened, etc.).
In otherwords, people who predominate these spaces of influence (what Michel Foucault calls "regimes") literally delimit human purview - they demarcate what is even thinkable through their gazes (frames). This, by itself, limits knowledge production to those with "legitimacy" and symbolic capital in various fields (cite: Pierre Bourdieu). It would be impossible not to diffract knowledge through the keyhole (minuscule,biased, experiences) of those who have accumulated power in society (regardless of the group). I'm much more likely to hear the thoughts of a Harvard graduate with a Law degree (Barack Obama/Ajit Pai) than I am a queer, paraplegic, woman of color living under an overpass.
The next question is how do you prove epistemological identitarianism? Well you'd assess the phenomenology of those in power--cite: "Being-white-in-the-world",etc. Robin Diangelo explicates such a phenomenology in her brilliant work on social fragility in her paper "White Fragility" gives us an affective map and phenomenology of hegemonic groups in society (maled, whiten, etc.). She outlines 10 taboos (defensive triggers, politically correct topic avoidances -if you will) that are iteratively deployed to, quite literally, create an intellectual safe-space that repudiate these triggers from ontology (this technique is called an affective technology- BTW):
10 phenomenological anchors that structure whiteness (and other dominant groups) & prompt definsiveness :
1.)White Objectivity - Suggesting White-identifying people report from a racialized frame of reference
2.)White Racial codes/mythology - POC racialzing their perspectives
3.)White Entitlement/Need for Racial comfort - Not protecting white Feelings
4.)White Maintenance of Colonial Relations - Refusing to produce a racialized account for whites.
5.)White Solidarity - When a fellow white person does not concur with white supremacist POV.
6.)White Liberalism - Calling out white racism
7.)White Individualism - Asserting that whites engage in "white identity politics" and operate as a collective.
8.)White Constructed Meritocracy - suggesting that resources aren't distributed equally among racial group
9.)White Authority - POC being in position of color.
10.)White Centrality and Dismantling of Stereotypes - challenges to white centrality. Requesting diversity. Requesting ends to white washing.
According to Robin Diangelo, within the rubric of the phenomenology of dominant groups are avoiding these 10 triggers -- that is this enumerates key affective states and epistemological limitations of dominant groups. The fragility thesis state that they'll avoid these triggers at all cost. The function of fragility is to "discipline" bodies to NEVER interrupt or question racial, gender, sexualized, etc. hierarchies in the West. Also, it arises from what Diangelo called a "racial equillibrium" that hyper-sensitizes dominant groups from being able to interrogate the impact of their hegemony. In the case of whiteness-- Sara Ahmed states that "whiteness functions as a form of social comfort that allows bodies to extend into spaces that have already taken their shape." In otherwords, the function of hegemony in generate is to minimize triggers for hegemonic groups and safe-spaces (keep space homogeneous and functioning like monoculture--through racial segregation, job discrimination,internment camps, etc.).
The fragility thesis is easy to prove. Go to Youtube, Quora, X.stackexchange.com,etc. and search for content titled any of the following "Why do white men__", "male privilege", "this is racist", etc. these phrases make the cardinal mistake of racializing whiteness, questioning male merit,suggesting white-identifying people can be racist, etc. so they'll likely have severe thumbs down not necessarily due to the merit of their ideas but the identities of those consuming the content (because the people who patronize the site are overwhelmingly 1 demographic).
More proof: Now look at your old college syllabi. I bet you "patriarchy", "sexism", "white supremacy", "heteronomative hegemony", "christian supremacy", etc. were never mentioned in any of your classes despite these being some of the most powerful social constructions in western society that determine so much. Also, how homogeneous was your faculty? This is proof of how homogeneity results in a identity-derived biases impacting knowledge and thus epistemology.
Nothing I am saying is novel. Foucault calls this the "Power/Knowledge" relationship, Bourdieu calls this "doxa", Diangelo simply extends Bourdieu to explain that ANY hegemonic majority group can socially construct a natural account of their "identity epistemology".
Even this well thought out response (I'm writing) isn't immune (I could be downvoted into oblivion, so these complex,but stressing, ideas aren't able to be debated-- such that only one hegemonic account is legible.
So to answer your question, epistemology is Always-Already "identity epistemology"--Whether we consider the dominant situatedness of epistemology (not POCs, not women, not queer, etc.) or subordinated subjectivities the author was carping about; it's still phenomenologically subjective. Philosophers of Sociology would probably go as far as to totally locate the domain of all knowledge (thermochemistry, probability theory, quatum physics, music, art, etc.) merely "Human Constructed" Truths.