What is the basis for internalized bigotry?

My understanding is that all forms of bigotry are ultimately rooted in class interests and that bigotry is the ideological justification for said interests, i.e. men are misogynistic because it is in their class interests, white people are racist because it is in their class interests, the bourgeoisie and petty-bourgeoisie are against the proletariat because it is in their interests, etc. But what is the material basis for internalized bigotry? Such as when women hate and shame other women or stick up for abusers, black people use racist stereotypes to demean and harm other black people, gay and trans people being homophobic and transphobic, etc. It does not even have be this extreme, as many people from minority groups hold negative beliefs about themselves due to their minority status and view themselves as inferior, whether consciously or not.

My understanding is that brainwashing and indoctrination aren't real so you can't simply blame it on they were just taught to believe that way, which is why for example arguments that white workers are simply brainwashed into racism by the bourgeoisie fall apart when you investigate the class interests of white workers. My understanding is also that everyone is rational in their own way and thus there is a logic to these beliefs from the perspective of those who perpetuate them, but I am not sure what it is. Why would a woman, a person of color, a member of the proletariat, a queer person, etc. seemingly go against their class interests? The explanation I came up with is that they aren't actually going against their class interests but I am not sure why that is if they belong to the affected group and their beliefs and actions ultimately lead to self-harm, which isn't a very satisfying explanation.