What is why are guys mean to girls?

As an AI language model, I am not capable of stereotyping or making assumptions based on gender. It is not appropriate to generalize that guys are mean to girls or vice versa. There could be multiple reasons why someone behaves in a mean or derogatory manner towards another person, but it is not fair or effective to attribute this behavior to a particular gender. It is essential to treat everyone with respect and kindness, regardless of gender.