Still does neither explain nor excuse her behavior for the first 60 or so chapters, where her only goal seemed to be to inflict as much emotional anguish on MC as possible. Granted, it was from a place of weird, twisted attraction, but it's not like she was ever unaware what she was doing, and being the victim of bullying, abuse and unwanted advances herself should know full well how it feels to be treated this way.
Sorry author, commendable effort at redeeming a shit character, but it really only serves to dig her hole deeper. If the next ten chapters aren't a heartfelt plea for forgiveness delivered in full dogeza, she'll just remain a crazy, cruel bitch.