A lot of people seem to be confused on what Ritsuka meant by "that side". This is up to my interpretation, but I feel like she means the side of people that, while not being homophobic, make a big deal out of same-sex couples and speak about it in a tone that makes it seem abnormal. Kozuka has done this before. She's not homophobic but she has made a big deal about it on multiple occasions. In the last chapter, Hirakawa was obviously making a big deal out of it, not to mention publicly outing her.