That's a very touching poem, but I think it could go much further. I'm actually not that upset that dogs are in cages at pet stores, it's not great, but I don't think it's inhumane. What bothers me about pet store puppies is that up to 50 percent can die on the way to the pet store. The markup is so great that they still make plenty of money when this happens. Puppies have to leave their mommy's way too early in order to look adorable to the customers.
Another thing that bothers me about pet store puppies, is that their parents are very often puppy mill dogs, responsible breeders aren't going to sell to a pet store. Puppy mill dogs aren't just kept in cages all day, they are crammed in cages, and have to relieve themselves in the same places they eat and sleep. They often get no medical care, it's cheaper to let them die, and replace than see a vet, who might even be tempted to turn the mill in. Of course, there is no grooming, and on certain breeds where grooming is not just a luxury, it's a necessity, this can cause extreme matting and pain when the skin grows together. Of course, there are many other cruelties that I won't go into. For those not aware of mills, this site has some excellent information, and this video shows the types of breeders who sell to pet stores.
View Investigation Report
Responsible breeder do not sell to pet stores because a pet store will not refuse to sell to anyone, if you got the money, you got the dog. Responsible breeders understand that not everyone should have a dog, and not every breed is right for every person. Responsible breeders place a puppy in a home where they can be fairly sure the puppy will be able to adjust to the family's lifestyle. Over 50% of dogs euthanized are owner surrenders, this means that owners are not be chosen properly, and since pet stores don't do any interviewing they are definitely part of the problem.