Just as I thought, teacher has no backbone at all, he was scared of class bullies and didn't take action, but when a popular girl got harmed suddenly grew balls.
Think that Takigawa might just be playing 4D chess, since she never talked to Kurosawa before, although it might be just a coincidence.
If Takigawa is a romantic interest and Kitahara just so happen to develop feelings, it's Kitahara who might just accept Kurosawa fetish.
Who would have thought curing sexual addiction at least for a day, would be because a honest talk with a girl you wanked off numerous times