I can see why people may not feel as sorry for the other critters in the pet store. For example, the rats and mice in the glass fish tank. If someone was to buy one, the chances of them living in the same type of setup are high. On the other hand, no one buys a pet shop puppy with the intention of it living in a glass box for the rest of its life.
I for one think no animals should be available for purchase at a pet store. but i don't have anything against specialty type stores selling animals, i.e - a stock farmers selling baby chicks.
Even when i was searching to buy a rabbit, many pet stores had them in class boxes with shredded paper and pellets in a bowl. Anyone who knows anything about rabbit health knows that pellets should be a very limited part of their diet, with hay needing to be in constant supply. I ended up buying my rabbit from a store none the less, but a store that specialises in rabbit/exotic animal care that has an on site vet attached to it.
I have often wondered what happens to the animals that aren't sold. Surely every pet shop cant have a 100% turn over rate...