For hopefully the last time, I'm not talking about the bacteria in the product. All human beings defecate. Many (most?) clean themselves afterwards with their hands. If you do not practise adequate hygiene with a surfactant-based cleanser, those faecal bacteria are still stuck to the skin afterwards and transfer to anything you touch, where they may be picked up by someone else who is not in a position to deal with them. This is not an appeal to emotion, it is a fact which I happen to have had personal experience of.
And again, the article doesn't speak clearly to handwashing specifically. It would seem that ideally, if someone believes in this kind of thing, the appropriate behavior when faced with handling something likely loaded with bad bacteria (which cleaning after defecation would include) would be to subsequently clean your hands with soap and hot water, and then reapply the N. eutropha.
