@reicchimaster To be fair, most cases with an older girl younger boy are when men are behind the story... in stories written by females, older men younger girls are more common.
I mean, let's not forget, the "High School Teacher marries High School Girl" trope exists or the fact that one of the first anime I loved, Card Captor Sakura had a romance subplot of a man well past his 20's being involved with an elementary schooler...
But by society standards, a female being with a drastically younger boy is more accepted for 3 reasons. Men had more power for the longest time, so if a man slept with a woman, it was him banging her. It was his bragging right. A medal. For females on the other hand, sleeping with multiple men made them a slut.
Second reason is because females in general have to fear rape and sexual harassment more (not that it doesn't happen to men, but females need to fear it more). So when a guy is in that situation, it bothers us less, cause while it happens, it's not as fear inducing for us.
Third, because among law makers and people in power, the majority are men, and our dream was to bang an older teacher... so why would we be against a situation we WANT to be in? We're too busy being jealous to get mad at her...