Ok, so I know this is about the most obvious suggestion possible on this subject, but if you haven’t, and if you get a chance, read The Handmaid’s Tale and its sequel, The Testaments.

They both have some really fascinating portrayals of women being or becoming complicit in the oppression of other women by a male-dominated system (while still also being oppressed themselves - their complicity is often a way of surviving in that system).

They’re obviously not the be all and end all of the subject, but they really made me think about the kind of people you’re describing, because I have (and still do) often felt the same - how can they do these things to other women?