Well, most languages use the masculine pronouns to refer to any group of individuals; it could have been one guy and nine girls, and you’d still call them “brothers” for shorthand in a lot of dialects. Kiku being lumped in as a man despite identifying as a woman isn’t the same as Yamato - there’s no confusion with the former, Kiku is Kiku and Kiku is a woman in her mind. At the moment, Yamato is Oden and Oden is a man, so Yamato is a specific man when she’s Oden; when she isn’t that specific man, the indication is that Yamato is Yamato and Yamato is a woman. As far as the confirmation bias, that knife can cut both ways…her continuously referring to herself as a man while in the Oden mindset is every bit as disingenuous as saying that the words “Kaido’s daughter” are the true misdirect.