In response to those responders who have chosen to blame the victim for not "standing up for themselves":
Have you tried asking why they don't react, after expressing some sympathy and before judging the victim?
One part of the lack of reaction to harassment is that “being non confrontational" has been trained into girls and women -and in this society- to varying degrees based on relative Caste of those involved.
Another part of it is knowing that they will not be supported by surrounding people, not even their friends. The difference in behavior of people in Delhi and Mumbai is telling: in Delhi, men can and do harass women verbally and physically with utter impunity. Women do not speak out or call for help when harassed on a bus in the daytime even when the harasser(s) stay right there a few feet away, smirking, because the women know it won’t get better for them and it could get worse. Women are at risk of much more egregious sexual harassment than described in the OA if they travel alone on public transportation. So they form travel pods of women or travel with a known man. (The above is based on the experiences of Indian feminist friends from Delhi.)
In Mumbai, on the other hand, the crowd on buses is in general strongly anti-”Eve teasing", people give women the benefit of the doubt (rightly so, given the a priori lack of motive) and come to the aid of women who have felt harassed — this results in Delhiwallahs visiting Mumbai trying their chauvinist stunts on the many more single women travelers in Mumbai and getting the shit kicked out of them by the crowd. Sensing this support for women, men are apologetic when there is unintended touch, which is inevitable on crowded buses and trains, and women in Mumbai are empowered to react by loudly calling out perceived verbal or physical harassment. More than that, women are even more empowered, I’ve seen women (one a college woman, the other a young middle age professional) simply turn around and smack the guy behind them- in one case the guy was apologetic and claimed unintentional touch, in the other the guy was angry, in both cases the crowd told the men, not the women, to be more careful in the future and to “move on".
Finally, don’t discount the non gendered effects of shock. I do not consider myself non-confrontational, but I’ve similarly been frozen into silence and on one occasion, laughter. (I’m an Indian man, moved to the US as an adult.) In a situation very similar to the one in the OA, a large white man approached me directly on a sidewalk in a downtown, approaching intentionally close, slammed his fist into my shoulder as we passed and muttered something racist. There are a number of things I could have done, but I stood there in shock starting at his back, and then just caught up to my friends and we laughed about it (Pam, this is your cue for blame-the-victim-ism.). The guy looked like a vet, so certainly my fear of retaliation played a part. Another incident was when two of us Indian men were walking home near US college campus on a Friday evening and a bunch of young white women in a sorority house upper balcony yelled targeted derogatory sexual come-ons at us. We walked on, in silence, with some embarrassed laughter between us and laughed it off at the time, but when we discussed it a day later we both felt shame. There have been other incidents of racist verbal harassment when I’ve not responded, but don’t worry, I know my place in America’s white supremacist Caste system.