Because men and women are different. There should be different standards for men and women.

When a female teacher sleeps with a male student, the primary victim is her husband.

When a male teacher sleeps with a female student, the primary victim is the student.

Sex is different, both physiologically and psychologically, for men and women.

In the case of the “female adult flashes a horny boy” trope, the reverse is not an adult male flashing a horny girl - it’s horny girl flashing an adult male. In both cases, the female is the one offering titillation because that’s how human sexual transaction works.

Because men and women are different. There should be different standards for men and women.

When a female teacher sleeps with a male student, the primary victim is her husband.

When a male teacher sleeps with a female student, the primary victim is the student.

Sex is different, both physiologically and psychologically, for men and women.