There are any number of reasons. For instance, I usually work late, so I have become friendly with the janitorial staff, none of whom know anything about biochemistry or molecular biology. But they are curious about the things they see me and other scientists doing when they come to clean, or about the equipment they see, and they ask questions. I can fully understand that scientist in the interview giving such a simplified explanation. Of course, I have enough background knowledge that I can pretty well surmise what is really going on at the molecular level, but for the lay persons, I see nothing wrong with the explanation as given.