With the bullying issue in this manga, I consider it as a joke since Esumi hasn't gone that far yet, or I should say she hasn't crossed that line to actual bullying. It's probably just me but I can see a difference between Esumi's actions and bullying in reality. Now when I was in elementary school, like many of you guys, I was also bullied. Stuff like a stronger kid twisted my arm for not buying her a snack, I got my lunch stolen, getting laughed at whenever I did something wrong or even when I read manga in class. That is bullying. While Esumi is definitely harrassing the captain, I don't think that is really bullying because back when I was in high school, my sempai(s) in Anime club always did this to me. It's all becuz I'm the only Asian girl in the club so they just loved messing with me like touching me when they hug me (they're all girls btw) or making me wear weird stuff even though I didn't want to. But I was okay with that since everyday was fun. Now that we have not seen the captain's point of view, we can't really assume that Esumi's action is hurting her emotionally like what bullying can do. What if the captain actually do feel like she's having fun with Esumi, despite of her being a sadist. This is merely my opinion, but yeah I think we should just relax and enjoy this because it's all in the past. And bullying makes you grow as a person so you should see it as a positive thing now.