Why do men harass women?

Answer 1

By getting more than just flirtatious and by ignoring indications that their advances are not welcome.
By unwilling sexual activities. That would include unwelcome sexual advances and requiring sexual favors from employees as a condition of employment or advancement. Similar applies at college if a female professor were to require sex from one or more male students as a condition for getting good grades. If a woman is a supervisor and the man gets fired or cannot advance unless he has sex with her, or she makes up lies on him accusing him of harassment for refusing to have sex with him, that is also sexual harassment. In highly competitive work environments, some employees file bogus sexual harassment complaints to try to get promoted. That is very nasty to do.

Answer 2

Yes. It is possible for women to do this. However, since this is quite often not reported and many males are unlikely to come forward with such an accusation, then such cases are not often brought to the media.

This is most prevalent in the workplace. If the supervisor is a woman then there is the supervisor/subordinate relationship. Then a man could lose his job or not get promoted because he refuses to have sex with her. That is sexual harassment.