Pedigree dog breeding is cruel, by doing so breeders actually keep deformities in the breed.
Take Rhodesian Ridgebacks, the ridge is actually a deformity.
This was refuted the last time it came up around here - the ridge is not a deformity, but breeding for the ridge increases the propensity towards generating a deformity - in this case, a mild form of spina biffida. It's a common misconception that the ridge is formed with this deformity, but it's a myth.