“If a rav says something is permissible it’s permissible even if he is wrong? I don’t think so.”
Are you arguing that one must fact check every psak given to them by their Rav, or to perhaps solicit the psak of several more rabbonim to ensure they get the same psak every time? The comment that the woman is following the psak of her Rav and therefore doing the correct thing, is a true and accurate comment.