Among the many other issues with trying to report sexual assault to the authorities, many of the individuals involved are anarchists or libertarians and don't want to involve state powers that they view as equally abusive.
Also, and this is where I probably sound like an as:
If you are an anarchist and don't believe in law enforcement OR in the ability of your community to replace them then tough shit if something happens and you have nobody to turn to. That is kinda the whole purpose od ordered society to provide a way to deal with that
Have you ever been sexually assaulted? (That's a rhetorical question, unless you actually want to answer.) It's deeply traumatic. In situations where you previously trusted the person who hurt you, it can be very hard to come to terms with what actually happens. Many victims feel shame. It takes time and often therapy to come to a place where you're ready to speak about it publicly.
(I'm not saying this is the experience of everyone who's ever been sexually assaulted, but it's an experience that has been commonly attested to.)
And yes, I understand that, the "immediately" was a bit knee jerk. But at least part of what you described is what I meant in another comment here: it should be part of both education and procedures to make immediate prosecution not only possible but a no brainer. Then we can avoid situations like this, which always reeks to me as "guilty until proven innocent"