I don't know...if the dog is a genuine working dog and has had all the appropriate testing done before being bred, I don't see a problem with it. People who work their dogs take great pride in working ability and I would think the best working dogs (the ones who prove they can do the job) are the ones who are bred.
Conformation showing isn't the only way to prove a dog is worthy of breeding. This bitch may well be a very good example of her breed and be excellent at the job she was bred to do, along with having wonderful health.
Without knowing more details about the people, the dogs and the situation I don't think it's right to judge her.
Now if the dog was a pet and she just bred her for the heck of it, that would be another story.
Cass.
ETA: "Showing" refers to the conformation dog shows. At their base they're suppose to help evaluate breeding stock. To help prove the dog looks the way it should look.