In this case a Chinese woman living in the USA apparently got raped in Germany 3 years ago. To involve law enforcement she would have to travel to a country where she doesn't speak the language, to make an accusation for which she has no evidence but her word, against a man who lives in another city.
What, exactly, do you imagine that the police are likely to do with her report?
I hate the court of public opinion as much or more as the next guy. But if this is a real pattern and he is as practiced as it sounds, after 10-20 women come forth then I'll be very confident that the crime is real. And there is also a chance that we can hit a critical mass where law enforcement somewhere may take an interest after all.
I agree with you that ideally this would go to the police first and they would actually act. But in the real world, she picked one of the best of the bad options available to her.