>>We can always eat the food we have by rotating.<<
That is exactly what we do.
What is the basis for the Red Cross recommendation to store supplies to last several days to a week? Red Cross recommendations to have food, water, and other emergency supplies on hand are not new, and are considered reasonable in case of any disaster. Our recommendations are to have supplies to last several days to a week. Most reasonable people would not consider such quantities of supplies as a "stockpile" or "hoarding."
Some families may choose to store supplies to last several weeks or more. Certainly, if they wish to do so, they may. It is always wise to have sufficient food and water supplies on hand in case access to such supplies may be disrupted by a disaster.
That's what we're doing. Caculating what and how much we need for specific number of people.