To be honest, I dont care about the breed of dog. If the parents are registered purebreds yet are not being shown to prove their conformation & their worthiness of being bred, and are not being tested to prove genetic soundness, it might as well be a mixed breed. And breeding mixes is on the same level as breeding unproven purebreds in my mind.

I have 2 dogs from rescue, one a purebred & one a mix. My Border Collie is from BCRNC, and I have fostered for them twice. They don't even ACCEPT any dogs from owners, only purebred BC's from shelters, because even with many foster homes in Northern California, they can only save a small fraction of the BC's dying in shelters. My Corgi mix had a purebred Corgi mom who was dumped in a shelter pregnant, and rescue thankfully took her in. Both of my dogs were saved from BYB's and both would be in a bad situation or dead right now if they weren't. Of course there are "better" BYB's out there, but the fact is they are ALL hurting dogs, whether that's from dumping their excess or unwanted dogs in shelters, or simply hurting the breeds genetically/temperamentally/conformationally.