Very interesting to read these arguments. This author isn't a dummy...he or she is toting a very fine line.
I think Hino's too shameless. Even if I liked someone in a lewd way, I wouldn't be pushing it like that until "I like you," "I like you too," was established. I don't get how she could actually just stand there and not go wait by the sink. That's what makes it fetish instead of respectful, and it takes away from Hino being portrayed as a human being. At least say like, "well if I wasn't in the stall, I could still hear you pee," in the moment. Anyone would want to make it less awkward in that moment, unless they're just an outright perv with no interest in the person as a person and not just a sexual object.
What I find more alarming is, "I have a childish body, so no one will grope me." Women in Japan better not seriously think that. I'm pretty sure 50% of men and lesbians are into child-looking women or girls. And most of them probably act on it at some point in their lives, whether it be IRL or porn. Because we live in a world where we're all hurt and "feel empty inside" like Hino because life is hard and people mean a lot to us. It's easier to objectify them and keep them at a distance after a certain amount of pain suffered from others.