Those who have operated during Ramadan with Muslim crew would understand the intent of the legislation. Fitness to fly is debatable after someone has been without food and drink for 12 hours, especially if operating a 4 sector day in summer. How does an airline deal with a Seventh Day Adventist who refuses a flight on a Sunday, or a Jew who won't work on the sabbath ? I've had first officers praying during the cruise and cabin crew that I was considering standing down due to the obvious effects of their fasting.
Air safety is one of the many things that should override religion.