Is it possible that some people see the value of their dog as being more than if whether or not they can generate $$$ from their uterus?
I can't believe how opinionated some people are about what good, caring owners are doing to their own dogs. I do not judge other people's decisions on how they care for their animals, as long as they are receiving good care. Leave them intact, or don't, I don't care, it's not my dog or my business. There are TONS of good breeding dogs out there, mine doesn't have to be one of them.
There are a lot more pet owners than people who truly work their dogs. There are some health benefits (particularly for females) to having the animal spayed or neutered.
I'm a pet owner who's interested in working my dog. I have NO interest in breeding. EVER. I don't care how well bred my dog may or may not be, I don't care how well she does in sport. I'm never going to breed her. There are many quality dogs out there who are bred by knowledgeable people who should be breeding. I'm a novice and I have absolutely no business breeding. My dog comes from good bloodlines, does that mean I need to keep her intact and breed her? She will never be for sale.
I had her spayed because it made the most sense to me. It virtually eliminated the chance of her getting mammary cancer, her personality remains completely unchanged, and frankly, on my flyball team they were complaining about two different intact females who shut down for weeks surrounding their heats, which makes them unreliable members of the flyball team and they have a tournament coming up this weekend that they had to pull them (two of their best dogs) from because they won't run.
All of our pets growing up have been spayed or neutered and they all lived happy, healthy long lives.
So I could see that a professional handler would want their dogs intact, because they are more likely to want to breed them. But I don't think it takes away from their performance if they are altered, actually I think it can help keep them more focused on the job at hand.
I'm a horse person, and trying to ride mares who are in season can be an awful experience, and stallions require a very experienced handler and your facilities need to be set up properly to accommodate a stallion. Geldings are a far more popular choice for riders, because they don't get distracted by raging hormones, are more even tempered, why would the same not be true for dogs?
If you're a pro who has an interest in breeding then, yes, an intact dog would be better for you. But I would not say an altered dog is less valuable. Less valuable to who? A breeder? There are more people out there not breeding than those who are.
There's a lady in our schutzhund group who was also a schutzhund judge. Her female is spayed and she just came in 3rd at the championships last year, the dog was sold shortly afterward. So obviously someone saw her value.
Not everyone wants to breed, and for those people, an altered dog can be a better choice for them. I find schutzhund people to be very forceful in their opinions and ideas. While I really, truly admire the sport and the amount of work and dedication from the handlers, I wish they'd mind their own business when it comes to the management of other peoples animals, unless it's a case of cruelty or neglect.