I'm going to throw my .02 in here. Yes, I have been sexually assaulted; twice. (Trying to keep this family friendly, so not going into details too much.)
I was a child, it was by two family members, and I was told by the priest that my father took me to for therapy that "If you hadn't worn the pink bikini swimsuit in the pool that day, no one would ever have touched you." Yes, it was the pink bikini on my 10 year old body that caused the whole mess.

The 2nd time, I had just filed divorce papers; and that didn't stop him from breaking in and, as the police put it, 'taking his husbandly rights'. (Not joking; y'all think the bad views of the Aurora CO pd started with the death of that young man? Nope, APD was corruptand bad policing the entire 15 years I lived there. My cousin was murdered, left in a school parking lot. Took over 20 years to get an arrest, then the case was over because of procedural problems with the evidence.)
In this particular case, the OP just reacted. It's understandable that she lashed out. I might have done the same. I would have definitely called the police, because as
@JimMIA has said, this guy has done stuff like the before. You have to report it, or they can't catch him; they can't try to solve crimes if they don't know it happened. He could have been a bit more tactful in the way he put it, but he's right. You have to report these things, no matter how small. The longer people get away with their bad behaviors, the more bold they become, and things can progress from a simple behind-grab to rape in the blink of an eye.