The narrator of "The Yellow Wallpaper," is meant to represent a certain type of oppressed women, specifically white, middle class women, or the type of woman that began the American feminist movement (I do not call the narrator an apt example of the oppression of all women, as society imposes different yokes of oppression on different women. Her story would be a bad example of the experiences of poor women (or women of color). In this interpretation then, we can show both that the actual character John is responsible for the psychological damage done to the narrator, and the oppressive institution that he represents is responsible for uncountable years of systematic abuse to the group of women our narrator represents. "The Yellow Wallpaper" is a feminist indictment of society at large.
Before beginning making that case, however, it is important to have at least a layman's historical and medical understanding of just what the tragic narrator was being treated for. The regimen prescribed by her husband and brother was one of the myriad acceptable treatments recommend for hysteria. The list of symptoms that has been applied to hysteria is too long by any measure to recount here, but practically it could be almost anything, as long as the patient was a woman. .
What we today recognize in the narrator as postpartum depression would have been diagnosed as one of the many manifestations of hysteria at the time Perkins Gilman penned her story. It relied heavily on the patriarchal trope that men, as a group, were rational, functioning human beings, while women at large were overly emotional, controlled by their uterus and hormones (indeed, one extreme treatment of hysteria called for a hysterectomy. The etymology of that surgery is no doubt an interesting one), a dynamic that is easily seen in the text. "John laughs at me, of course,"" (Perkins Gilman, 1) the narrator tells us, and calls her "little girl," (Perkins Gilman 7) because he dismisses her misgivings on the house as the suspicious, irrational musings of a childlike woman.