Well, there is always the chance that she went to that fight figuring it would help to stop the practice, especially since the guy definitely looks like a man, and most people really do dislike the idea of men beating up women. Even the ones who have watched too many movies and think it is possible for a woman to beat up a man won't like watching the opposite to happen, so seeing it happen is certainly a nice reminder for them that yes, that is the most likely end result, no matter what the movies and some idiot activists may claim.

Although the bigger reason is probably just that since she had gotten that spot in her countrys Olympic team she didn't think she could refuse the fight on the last moment, so she just went and did her best.