I read an article recently by a psychologist about why the focus on toilet paper.  The article said that because of the size of the typical toilet paper package, stores typically cant devote large areas of shelf space to it and when the limited number of packages on the shelves are gone it creates a large open space, compared to say soup cans. Pics of empty TP shelves get published because they are more visibly empty due to large package size and then a group psychology sets in and others start buying more TP than needed.

This doesn't happen as much with smaller products, which have visibly less obvious empty shelves. So the article went...