The minister has mentioned that this is because "the sensitive role of the country's women in the elavation of the Islamic society and the necessity of effective presence of ladies in the warm focal point that is the family, in order to fulfill the sensitive responsibility of educating the children". I won't say much about the case of mothers, but if you don't have children at home to raise, I guess it's only the first part, your sensitive role in the elevation of the Islamic society, that applies to you. So, logically, it seems that the new minister believes that if a single or childless woman leaves work at 6 pm (or earlier), their absence elevates the Islamic society.
It may not be a coordinated act in the whole administration and may only be random opinions of inexperienced public servants, but it still takes its toll, and results in seeing less women in the society. As someone who has tried to help a few women find their place in the work environment, I am very concerned about this.