i think speakers and fiqh texts must be precise when presenting a fiqh ruling. if someone is haram, then it must be stated. e.g. it is haram for a menstruating woman to offer salah and fast. hence, it should not be stated that: "sisters are allowed to miss the fast" or "it is not necessary for them to fast" etc. the ruling must be clear that there is no second option for them, i.e. "it is haram for her to fast and she would be sinful if she does." --- btw, what if she considers it permissible to fast?