I still feel like the parents are more to blame than Haru in this case. The way it opened with Haru telling her mom she won an award only for her mom to totally brush her off and focus entirely on the younger daughter just leaves a bad taste. Winning first place in anything is a pretty big thing, so I can totally see why Haru was so resentful to her younger sister in that moment. That's one of the few times where you DESERVE to be the center of attention.