Because those are the ones they are required to list.
The list of items on the Nutrition Facts panel is the same no matter what you are looking at, so foods that have none of some item will always list it as zero.
For the record, you should find something like the following on any food product.
Nutrition Facts
Serving Size: XX
Servings Per Container: about XX
Amount Per Serving
Calories XXX Calories from Fat XXX
Total Fat Xg x%
Saturated Fat Xg x%
Cholesterol Xmg x%
Sodium XXmg x%
Total Carbohydrate XXg x%
Dietary Fiber Xg x%
Sugars Xg
Protein Xg
Vitamin A X% Vitamin C X%
Calcium X% Iron X%
“Sometimes I think the web is just a big plot to keep people like me away from normal society.” — Dilbert
Actually, you will see some food products that don’t have nutritional information on them. Most of these are produced in the state in which you buy them. The others are violating the law. The nutritional information you see on most food products is required by national law. This law only applies to foods that cross state lines. If a food product is sold in the state in which it was produced, it is up to the state to regulate the labeling information. I believe that most states do not require very much info.
Things are random only insofar as we don’t understand them.