Telling Use of Language --- If you aren't totally clean, you are filthy

This is a phrase I saw on a hand soap advertisement awhile back. The ad had a picture of a hand covered with oversize germs that were creeping along a person's skin towards a spoon she was about to put in her mouth. I was repulsed by this but also somewhat confused. Cleanliness does have different degrees. There are also degrees of being dirty. To be covered ask is to be dirty but to be covered in crap is wholly another kind of dirty. It's not either you are clean or you are not in the case of dirt and germs as we all need a certain amount of bacteria and germs to maintain homeostasis.