Because they are exposed to misogyny everywhere.School dress codes are designed to keep girls from distracting boys. So boys aren't expected to control themselves, but girls are told that they are responsible for boys behavior. If a boy grabs a girl, he must like her. People use phases such as, "Throw like a girl," or "Cry like a little girl," all the time. Or people say, "Boys will be boys," as a way to excuse bad behavior rather than punishing it. There have been literal books written about how misogyny is woven into society.You can teach your children whatever you want at home, but society is teaching them something totally different.