Can someone explain to me why Red Cry killed Hana's mother?

I have never understood why Hana's mother was killed. She was propped up as if on a stage to be judged for what? For being homeless? For being a homeless minor taken in by an abusive adult man? For hiding her kid out in the center instead of keeping her at the killer's home?

I might very well have missed some context as I always do something else while watching tv shows, but I just cannot for the life of me understand why she was killed,