I had willed myself to believe the previous explanation, that Jack was a broken man, a man who had tried since he was a kid to remove a piece of his puzzle that would only do harm to himself and those around him. That Grace and Anna would instead be pieces of his puzzle that were never meant to fit, but could be jammed in hard enough that the bent and broken tiles eventually filled the empty spots in his life. But when you see the entire puzzle of Kill or Love together, it looks just as jumbled, nonsensical, and disappointing as Jack turns out to be.