Too add the only reason the other guy also does this is because he still sees the world as a game. He doesn't see his friends classmates or anyone else as real people.
Yes, both in the Novel and the Manga he treats Kaoru as a game character and thinks that he only needs to show a bit of strength, and she will be in love with him, but that doesn't happen.
Even Souta noticed the obvious that the players only see the things from Akagi or Sakurako's perspective, depending on the route.
The truth is, Kaoru falls in love with the protagonist due to a combination of wanting to get rid of Souta (who becomes creepy and a stalker) and Akagi being her role model.
In the game, she never told anyone that Souta and she were childhood friends. Here her comrades knows that they are CF's because she was fine with him.