My 2 cents: I have owned dogs all my life. Worked as a vet tech, and volunteer at a large, animal shelter.
First off, indeed, some of the people that get into animal rescue work are, 'over-the-top' militant. There is only a special few, fit to adopt one of 'their' dogs.
At my shelter: they are sneaky when they get a litter of pups. The small-breed pups usually never make it to the adoption floor. They are adopted by shelter employees and their friends. The pit bull mixes go out on the floor. I, personally have a shelter pittie and she's one of the best dogs, ever. But, they are not everyone's cup of tea.
As much as anyone at the shelter would keel over, if they heard me say this: There is nothing wrong with getting a pup from a quality breeder. Find a good breeder. See the parents, before the litter is conceived. See the pups as they grow to adoption age. Choose the pup, based on the parent's, temperament/health, the pup's hierarchy in the litter, (the Alpha pup may be too headstrong), and results of previous litters with these two parents.
This is going to a member of your family for a long time. It's important to know everything you can about the pup.
I know all about the, 'For every dog purchased, a dog is euthanized' credo. Plenty of people that would give a dog a great home, are turned down by shelters/rescues because of the strict rules. There is still a place for conscientious breeders.