Tomoko has a thing for abusiveyandere men. Now it's just fantasies and video games, but when she's older...
Considering how her mother is known to slap her on some occassions (generally deserved), she is definitely not unfamiliar with the idea of a beloved family member hitting her...
Additionally, just how far might she go in order to get laid? Venturing into the red-light district scared her, but again, when she's older...
Alternatively, she could be an abusive yandere herself, if she's desperate enough.