Why do Muslims believe not all people need to fast?

Some Muslims believe not all Muslims need to fast because Islam teaches exceptions can be made for health reasons. This teaching is reflected in the Qur’an quote, “anyone who is ill or on a journey should make up for the lost days by fasting on other days”, which infers, if fasting poses a health risk for some such as pregnant women, children, and the ill, they have permission to fast when it is no longer a risk.