The woman did not say she was raped until the next day. They found a lady at 1am slumped over on the side of the road. They made arrangements for her to get home when noone would pick her up. I cannot blame the cops.
The cops may have been able to charge her with publice drunkeness (my assumption) or even indecensy, but they didn't.
It is easy to say, but yeah, the cops should have known she was raped. How? You can't go around planting ideas in peoples heads saying "perhaps you were raped tonight". That is bad therapy practice, not allowed in court, etc. Can you imagine how that court case would go.
But ma'am, when police found you, you didn't mention that you were raped. You didn't mention that you may have been sexually assulted. You were with the cops for a while as they walked you to the cab companies place of business. They then waited with you to see if someone would come and pick you up. When noone would pick you up, the cops asked the cab company if they would take you home. You were with them a long time and never mentioned this alleged assult - that is until the officer asked you if you were raped. At that moment your story changed. Yes, there is evidence of a sexual encounter, but it is difficult to say whether it was rape if you didn't claim rape until it was a convient way out of your problem of being a drunk heep on the side of the road"
I'm not saying that is the right way to treat the victim, but that seems like a mild version of what the court case would sound like if the cops "planted" the rape idea in her mind.
I think this is a sad scenario and I feel bad for this woman. I hope she gets the help she needs, but I simply can't fault the cops for this sad situation.