Rachel is a big mystery to me, the only thing we know for certain is that her behavior doesn't stem from an abusive father. She could be weird like that, but I think we will get some sort of explanation.
One idea is that she just got radicalized online, which, while plausible given how common that is, would be a real boring explanation (but maybe the point isn't how she got to where she is but how the MC will help her out of it)
Another one, as you said, could be something from her mother. There are a few things that it could be, her mom could be just a raging misandrist, instilling those values on her child. Or she could be doing parental alienation, she and the dad are divorced, she got custody, and spends a lot of time lying to Rachel about how awful of a person her dad is, if this happens young enough it could turn into Rachel being generally distrusting of all men.
Whatever the reason is, I am excited both to see it, and also to see the threads reaction to it

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