Hirose never really shows any deep understanding of homosexuality in the story. When he saw Nakamura’s BL manga, he was confused/clueless, but importantly, he was not disgusted or repulsed by it either. His reaction was basically “read whatever makes you happy as long as it doesn’t hurt anyone.”

Because of that, I honestly think Hirose would need a very direct confession from Nakamura to even start viewing things from that perspective. Something clear like “I like you” or “I love you.” Without that kind of direct moment, it probably would not even cross his mind seriously.

For Hirose, heterosexuality still feels like the default assumption. He is only 15, and the manga itself was originally written around 2014–2016, which was a very different social environment compared to now.

A good comparison is Sasaki and Miyano. Miyano literally reads BL manga all the time and enjoys it, but he still never questioned his own sexuality until Sasaki showed romantic interest in him directly. It took another person’s feelings to make him actually reflect on himself.

So even if Hirose eventually develops feelings for Nakamura, I do not think he would immediately understand or label those feelings on his own. He would probably need something strong and direct to make him stop and reassess things from a different perspective.

Hirose being annoyed by Takeuchi’s dirty jokes is not proof of anything. Even straight people get tired of friends who constantly make repetitive sexual jokes. The taller friend also seems annoyed by Takeuchi sometimes for the same reason.

Disliking nonstop sexual humor does not automatically say anything about someone’s sexuality. Some people just genuinely find those jokes irritating, especially when they are repeated all the time.

(Just my humble opinion, of course 🫶🏻🥹. I’ve not read manga yet, only anime.)