@Kamui
violence is necessary to create a bad sad and a good side if both were passive there'll be no villain and therefore no story
and depending on some circumstance teaching kids that defending their right is important too or else children will accept any abusement to them without fighting back
but sex is something private and should be private it's rule that was created to keep us sane and not scumbag to our filthy animal instinct and to think about making a stable family once we are adult
rape was also a taboo for obvious reason (creating a very shitty family with a non loving mother and abusive family relatives )