I don't think it's terribly relevant as Kidoguchi knows Shimizu is gay, right?
He doesn't know for sure. Shimizu has only come out to Maekawa. So even if Kidoguchi suspects it, I don't think someone who is not certain of someone else being gay or how comfortable they feel openly talking about it, would use a female pronoun.
Not trying to argue, just my two cents. Seems like "they" would be more appropriate here, considering the fact that he doesn't directly use a female pronoun in Japanese as well.
So, there are no gendered pronouns in Japanese, but in English, gendered pronouns are so common that people consider it conspicuously out of your way to use they/their/them. This adds a complicated subtext to a lot of manga, especially queer-genre manga, because you can give the impression that someone is guarding their sexuality when they're actually speaking frankly, or you can give the impression that someone has been "tipped off" to things they're already supposed to know, or any number of other little mischaracterizations.
I believe it's generally suggested here and from past conversations that Shimizu doesn't really have any secrets from Kidoguchi. He almost certainly knows she's a yuri fan, and that she ships girls constantly. We also know that they broke up -and- they're still good friends, which suggests comfort and honesty. He may or may not be explicitly aware that she's gay, but he probably has at least suspicions, and this is supposed to be a scene where she's bearing her soul to her most trusted friend. It changes the dynamic if the translator writes it as if she's in the closet with him.
All in all, I think it's a complicated question with no easy answer. I suspect it's immaterial anyway. He probably knew anyway and there's a good chance he recognizes that it's Maekawa. (Now, anyway)
last edited at Aug 20, 2019 6:10PM