When Kanroji actually told Iguro she was trans, he didnt actually know what she was talking about so he just went 'ok'. He had and really has no idea how sexuality works. He did eventually learn what being trans meant, but he couldnt find a reason not to want to be with her. She was literally everything he could have asked for. Iguro also never really looked at her in a sexual manner or thought about her body like that. So to him it was completely insignificant.
Aside from like...dysphoria days and stuff (which when Kanroji gets like that Iguro tries to help) he literally doesnt give a single shit. Nor does he care if people know hes with a trans person. He cant find the issue in anything except other people's attitudes. However its rare for Hashira to say anything, demon slayers definitely do. And they never say shit again by time hes done.
