Why do young boys sexualise their female teachers?

I have come across so many posts where people make double meaning jokes on female teachers in the name of 'humour'. I have also come across a post where one teacher shared her experience that she was slut shamed by her class boys who were just around 13-14. And also I have observed this in India too. One of my friends (she was from different school) shared her experience that her science teacher was amazing teacher but she quit her job when she realised that few class boys would ask her questions deliberately to take a sneak inside her blouse and laugh over it. She honestly felt so hurt because she was such a devoted teacher and taught every student as her own child. Some actually might not believe and I am definitely not bluffing. But it's so disappointing that young men don't feel remorse towards their actions and 'SOME' grown ass men would excuse their behaviour by asking "well what were you wearing?" "You are an adult you should know how to handle it??"