I do not assume all purebred dogs are from breeders. My family has an Irish wolfhound and a great Pyrenees whom are both from rescues.
I have had many, many casual conversations with people at the dog parks, and a lot of them come from breeders. I even heard someone complain about how her "mini" dachshund she bought was not actually a "mini", so she was going to get rid of it and get another one.
I guess I have just grown a bit bitter because of some of the people here, haha, I am sorry.