People are not required to think about the food, so they don't. For example, it's widely known that milk comes from cows, but not that the cow needs to be pregn

People are not required to think about the food, so they don't. For example, it's widely known that milk comes from cows, but not that the cow needs to be pregnant in order to do so, again and again. It's just not something that one faces in their day to day life. These things just spawn on supermarket shelves, and that's about it.