@Aretheus You seem to be forgetting that there are clearly rumors and other bad associations with regards to Furi, both from her appearance and attitude. Taira's interactions with Furi are obviously influenced by these rumors and assumptions about her, and her general lack of communication skills (due to maiden-like embarrassment apparently) cause her to not vocalize things properly in order dispel any possible misunderstandings. He doesn't know why she seems to be targeting him because she hasn't really said anything, and due to the influence of his assumptions about her character he seems to believe she might be somehow trying to bully him, at least at first. Also, the scene with them volunteering for the same class assignments could be inferred this way... that she was trying to pair up with him so that she could push all the work onto him (a very delinquent-like thing to do to a "beta" character), which is why he was trying to avoid getting paired with her. All of this is because of her supposed reputation, and she is doing nothing to change that.
However, despite all that, Taira is at the least being courteous to her, and becoming at least somewhat conscious of her as a girl. He doesn't notice the small hints she's giving that she likes him, because he has no experience with girls, and those hints are very vague anyways.... especially when she puts her foot in her mouth by not saying what she means properly. That is actually a huge difference between these two stories, since the relationship between Toramura and Unoki is based completely on a misunderstanding caused by a lack of communication and Unoki's fearful subservient attitude caused by his traumatic past. Meanwhile, Taira and Furi merely have to get to know each other better to realize that his assumptions about her were wrong, because she's not an actual yankee like Toramura is. Honestly, it's unfair to compare the two because of this point, since the situations are not the same. Unoki has a VERY real reason to be fearful of Toramura, because she is an ACTUAL yankee, while Furi and Taira just have to actually talk to one another properly. However, proper communication has to be initiated by Furi herself. Taira is unlikely to do it because of her rumored reputation and his assumptions about her character. It's unfair, sure, but she needs to be the one to step up and clear the misunderstandings about her to him.
Now, before I sound TOO preachy, I will say this. I don't like misunderstanding romcoms all that much. They tend to drag on the misunderstanding too long, and I feel there is something fundamentally wrong about the genre, since a proper relationship is based on having good communication... which the cornerstone of basically all misunderstanding stories is a lack of communication. However, I feel like you are being way too harsh on these characters. I won't call them realistic, but I can definitely understand why Taira acts the way he does towards Furi, and I know for a fact it happens for real (at least to a certain extent). To be perfectly honest, I feel like the blame for the misunderstandings lie MORE with Furi than with Taira because of her lack of proper communication, than for his assumptions of her character based on her appearance/attitude/rumors. I find it hard to believe that she doesn't realize how she dresses and acts might make people think what they do of her.