Abusive treatment is not part of her sentenced requirements. Her being in custody is her punishment, not inhumane abuse while being in custody. Yes, inmates shouldn’t be treated like delicate little flowers and need strict legal discipline and to be treated with a blunt and straight-forward attitude if they do not behave accordingly to the law and the institution’s inmate rules and regulations while incarcerated.
Being convicted does not automatically authorize guards or any jail/prison employees to purposefully punish inmates just for being an inmate. There’s a difference of not being nice to inmates and tormenting inmates for self-satisfaction or just because they can.
You don’t spank a child or put them in the time-out corner at random throughout each day of them being grounded for no reason besides the fact that they are grounded. The grounding is the punishment spanking them at random each day is torment. Big difference.