I think you are misunderstanding the nature of the rule.
It only came about because it was observed that the ‘hot’ female teachers were not being punished as severely as the ‘not so hot’ female teachers.
It may have come about that way but it has morphed. I have seen men on this site defending a women pedophile because they would have liked to have slept with a hot teacher when they were young. They don’t think the boys are victims. It happens on every thread about a female teacher.