As with most species of domesticated creatures, there are people who breed their animals for quality and integrity of the line, and then there are people who simply let their animals breed for the sake of reproducing.
Certain breeds of animals were designed for specific purposes. For example, consider, if you will, the labrador retriever. And let's assume that the breeder of the labrador dogs cares greatly about maintaining quality in his dogs' bloodlines, and thus adheres to all standards set forth by professionals for that breed. If certain dogs of his begin to show signs of regular hip displasia in the pups, or perhaps other poor characteristics, such as chronic overbite, out of responsibility, he desperately needs to change his breeding program and discontinue using parents who are passing down traits in the pups which are damaging to their ultimate functionality and well-being as adults. These pups may be adorable and sweet, and many families might love to adopt them to give them good homes as pets. However, they would not be good for breeding, as they'd continue to genetically pass on traits which cause the dogs great pain in adulthood (such as hip displaysia), or difficulty with other functions because of malformities.
Similarly, that's how responsible animal husbandry works with pigeon fanciers. Responsible fanciers maintain breeding charts and pedigree records for their birds. They evaluate the health, form, and successes of their bird pairs' off-spring and adjust breeding programs accordingly.
For those who race their pigeons, results from races often reveal the best of bloodlines/homing abilities/health of his/her birds. The best birds make it home quickly, reliably, and safely. The bloodlines of those birds are the ones the fancier will want to continue pairing together, always striving to maintain quality and soundness in their pigeons. They will often pair their birds with purchases from other lofts: New "blood" proven in races, ever striving to produce the best. Comparing these athletes to feral pigeons, would be like comparing a champion race horse to a plow horse.
For the pure white homing pigeons raised for training for releases, the same applies. The best, most responsible breeders are ever-striving to improve their stock, making certain their beloved birds are kept in tip-top health, and striving to use quality bloodlines from proven families/pedigrees. It is imperative for the dove releaser to use healthy birds with lovely form. It is also imperative that these birds have the ability to return home quickly from each and every release. God has given us dominion over the animals, and it is our duty to care for them in the very best way possible.
There
are a very few breeders who let their birds breed haphazardly in the lofts. Some have so many birds, they don't even bother to band them or keep track of the bloodlines. They don't concern themselves with the integrity of the physical standards of the birds, nor do they care so much whether or not the birds have strong homing instincts. They may have 500 birds in their lofts and in their minds, so long as the birds continue cranking out off-spring, they stand to continue making money off of the animals. Again, this isn't even remotely acceptable, and is deeply irresponsible.
Now, if the birds in the loft are all at a good quality level and have proven themselves, then allowing them to choose their own mates is, in my humble opinion, not harmful at all. I would still hope that good breeding records would be kept. However, if the breeder has full confidence in all the birds he/she has, there should be no problems. With careful record keeping, if any problems did arise in a young bird, they would be traceable.
The WDRP rule requiring the practice of careful animal husbandry from its members was created for purposes of perpetuating highly responsible loft management, and thus doing a great (and absolutely, unquestionably necessary) service, in protecting the birds.