Kurosawa would never have tackled a subject like this. He is interested in active people- people who make a difference- and the point about O-Haru is that she is entirely helpless.
Helpless in a society of helpless people. Even those who abuse O-Haru are trapped. The Lords (father and son) are the prisoners of their courts. This is society without any give. People who threaten its codes- O-Haru's low-born lover, the forger, the thief she runs off with- are all immediately slapped down.
O-Haru's virtue is endurance. She carries on in spite of everything. Reduced to beggary, she bows her head as she passes a pagoda. Thy will be done.
But there is no consolation in religion. When she seeks shelter inside a temple, the ranked boddhisattvas present her with a wall of indifference. Remote, uncaring, and all male, they are simply a translation into the spiritual sphere of the hierarchy that has used and rejected her.
The worst abuser of all is the "old religious man" who hires her so he can display her to his disciples as an object lesson in degradation- a goblin cat. She has nothing more to lose; demonized, she becomes a demon with a demon's power to disrupt and alarm. She advances on the old fraud, waggles her fingers and goes "boo"- and momentarily scares him out of his dignity. It is the film's most heartening moment.
(At the beginning- where the old whores gather round the brushwood fire- is this a conscious echo of Villon's La Belle Heaulmiere?)