It's not that baffling. Being a victim of harassment raises your status in certain circles. People in those circles tend to accept your word without requiring any other evidence, and so naturally some people will find harassment in anything that happens to or near them that can be stretched or interpreted, no matter how far fetched, in some way to be harassment.
This is bad because it makes it harder for actual victims. Too many people making exaggerated or false claims will make people less likely to believe the real victims.
This is probably more general. In general, if some event raises status in a group a person is in, and claims of that event are hard to verify, some people will claim the event even if it did not happen to them. They may not even be knowingly lying. They may be convinced it did happen.
A couple examples are having Native American ancestry and being abducted by a UFO. Many people claim one or both of these, and there are groups in which those claims will raise your status. Result: a lot more people claim Native American ancestry than actually have Native American ancestors, and the number of people who claim to have been abducted by UFOs is way higher than the number who have actually been abducted. My guess would be most of these false claims are from people who believe they are telling the truth.
The desire for status in the groups you are in is very strong. For instance, I recall reading a book about the major criminal gangs on Los Angeles, and they talked about status within the gangs. One of the things that earned you higher status was being arrested, refusing to talk or cooperate, refusing to take a plea bargain, and getting sent to jail. Gaining status was so important to new, young teen gang members that they would purposefully commit crimes that would get them a few months incarceration so that they could gain the status. Note that unlike UFO abduction or Native Ancestry, serving jail time is verifiable, so they young gang members cannot simply claim they served time to gain the status. They actually have to do it, and they do because gaining status is that important.
Any evolutionary biologists here? I'm curious if our need for status is just a cultural thing, or if it predates culture? I believe that most of our current close primate relatives live in groups where status relationships are very important, so it seems at least plausible that this is something that developed very long ago, in the common ancestors we share with those other primates.