Islam critiqued discovers bloody truth; who are the non-menstruating women?

In answer to the video "Surah 65:4 and Child Marriage in Islam"

There are several physiological reasons for otherwise normally menstruating women that might cause them to fail having their courses, including pregnancy, medical conditions, hormonal dysfunctioning, stress, too much physical exertion, diet etc. It can be delayed and some women may not bleed very much, to the point its hardly noticeable such as what happens in the menopausal stage, before the postmenopause which is the period where women cannot get pregnant anymore. Those women "who have not had their courses" therefore covers all these categories.

The verse also speaks of those that might be in postmenopause and unable to carry children anymore but one isnt 100% sure they have reached such stage, hence the words "if you have a doubt" in the phrase

"And (as for) those of your women who have despaired of menstruation, if you have a doubt".

It speaks of women in a condition of despair as regards their monthly courses, women who are beyond the normal age limit and who have not had their courses anymore as they should. Any woman who has seen the effects of that natural phase in other women knows how well off she was during her menstrual phase and relatively mild bothersome symptoms that she experienced. In comparison there are much more increased risks of health issues to a postmenopausal woman, like heart and bone diseases among many other conditions, not to speak of the mental factor of having to accept infertility, especially for those women witout children and who married late.

Some unsuccesfully tried to argue that since postmenopausal women must wait 3 idda despite them not having had their courses for a long time and having only a slight chance at pregnancy, then nothing negates that prepubescent girls must also wait 3 idda since, just like the former case, they too have not menstruated for long and in addition they too have a little chance of pregnancy about a month prior to their first courses.

However the wording denies their inclusion. Although one may "doubt" whether a pre-pubescent girl with whom one had intercourse is pregnant or not, just like one may doubt if a woman in postmenopause is pregnant, a pre-pubescent girl is certainly not one who has

"despaired of her menstruation".

Only one who is well into, if not already passed the normal age range at which women become postmenauposal, qualifies as "despaired of her menstruation". And besides, to include prepubescent girls among those who have "despaired of their menstruation" would entail they are well into, if not passed the normal age limit at which girls get their first period, ie the very late teens.

This of course, doesnt serve the purpose of those claiming the Quran allows marriages at very early ages.

An important thing to note here, in regards to the precision of the verse's wording, is that "doubt" over "possible" menstruation doesnt cover 

"those too who have not had their (menstrual) courses". 

The advocates of prepubescent marriage need the "doubt" to cover them but it doesnt. It only concerns the women who are in postmenopause as described earlier. "those who havent had their courses" are women, agaoin, flagged as NISAA', of menstrual age and in addition have already actually menstruated. They are fully expected to keep on menstruating, but they are not currently for the physiological reasons already given.  

The purpose of the 3 month waiting period of idda is to determine if the woman about to divorce is pregnant 2:228. For a woman who is expected to menstruate normally, such delay might almost certainly mean pregancy and also the womb starts to take on visible signs of pregnancy at that stage. This is why 33:49 states those that are divorced prior to sexual intercourse do not have to go through the idda waiting period. Obviously without sexual intercourse, there is no possibility of pregnancy.

That the issue of idda is all about ascertaining potential pregnancy via menstruation is also seen with the second part of the verse 65:4 which mentions the case of confirmed pregnant women, while the first part dealt with those that were potentialy pregnant, saying their waiting period is no longer 3 months, but the whole length of the pregnancy. In light of the above, the lack of menstruation concerns specifically women who are EXPECTED to have their period, which isnt the case of pre-pubescent girls.

There is a reason the Quran contrasts the menstruation in terms of expectation (potential pregnancy) versus non-expectation (confirmed pregnancy). The fact that one claims such a verse refers to girls that can't even get pregnant is the utmost absurdity, because nobody expects them to get pregnant.

Additionally, if one argues it does refer to pre-pubescent girls, then it renders the whole argument that consummation can only happen after puberty as null and void.

During both cases -that of a woman potentially pregnant having to wait for 3 idda and a confirmed pregnant woman having to wait until delivery- the man must fully sustain the woman without any kind of oppression, though they are going through a hard phase that will probably end in divorce 65:6-7.