Puppy mills. Any time a breed gets popular, those pieces of shit will start breeding any two dogs they can find with no consideration for temperament or health, and idiots pay through the nose for them. Then they're shocked when the dog they were promised would be smart and affectionate is anxious and aggressive.

I had a rescue doodle that came from a puppy mill that shut down, and he was in horrific shape. He physically couldn't sit for probably a year because his hips were in so much pain. I took him to a groomer and she had to shave him before and after his bath because he was so filthy and matted. He jumped at every loud noise for years. He was also incredibly gentle and sweet once he trusted us, but it was clear that the woman who owned him only cared about the state of the puppies, and kept the parents in appalling conditions.