Jashin, you say...?
Regarding the questionable panels: While I do agree that it shouldn't be a problem with showing characters taking a bath, people do have a point about the way it's shown here. The angle of the panel is really unnecessary, it's almost as if we really have to see the naked body of a pre-teen girl close. Other manga have showed characters taking bath, even naked, without issues: Persona, Dragon Ball, Naruto, Wataten, Doraemon, Detective Conan, and so on. It's not the showing of a character in a bath that's bad, but how it's done. Maybe this is just the author/artist's way of making a joke, and this sense of humor doesn't work very well. If that was fanservice... who the hell was it aimed at?