Small potatoes. I can't imagine legal action helping much. Move on from the unpleasant experience and help others who face greater injustices.
If they're continuing to harass them as described, it seems like a prudent choice.
What burden of proof?
To me that would indicate some serious "boundaries issues."
In cases where someone feels harassed "judgment" isn't necessarily even the point.
Legal action is taken, you get a lawyer, they get a lawyer... often their lawyer tells them not to contact you or people you know anymore (because that is what a good lawyer will do) and it is effectively resolved. For some people that may be enough / the entire goal and it can cost as little as everyone talking to a lawyer once.