Critical Thinking vs Shariah Part 50 Ramadan Fasting Part C

Shariah reveals that women are given an exemption to not fast. It also provides reasons a fast can be invalidated. But does that mean fasting in the month of Ramadan is invalid for that person? Is a fast to promote a person's being seen as a devout follower of Muhammad, or does it have an inward purpose? What if Shariah says something about fasting that makes you wonder if those who wrote it knew what a fast is?