Here is a good article to read about pet stores, hobby breeders, commercial breeders and puppy mills.
http://www.canismajor.com/dog/puppymil.html It makes a good point that NOT all pet store dogs came from puppy mills.
As all things in life -- they are not all the same. There are good and bad hobby breeders, good and bad commercial breeders, good and bad pet store owners, and good and bad PET OWNERS too. A person just has to use some intelligence and cull the good from the bad. Once people have their pets, they just need to love them and give them the lives they deserve no matter where they came from. JMHO -- and a novice one at that!