Some people are just OCD about germs and cleanliness. Nothing you could say to these kind of people would convince them it is okay to drink after your dog or to let them lick you on the lips. The fact is it just grosses them out. I feel the lady should of kept quiet but some people just can't mind their own business.
One thing that bother me is when parents with children will not allow their children to have a pet because they don't want their child to get germs. The truth of the matter is that pets can actually increase the immune system of children.
Dogs, Cats Reduce Risk Of Allergies In Kids