I think there are just so many irresponsible owners who allow their dogs to produce "oops" litters, that vets (and breeders!) feel that they need to encourage neutering of all pets. But as Roki said, in Europe, neutering males is MUCH less common, and the dogs learn to behave properly and are kept well away from ladies in heat.
That said, I do think it's a frustrating life for an entire dog to never be allowed to mate. I also know for certain, from watching all my friends who have breeding dogs that they also do performance sports with, that it takes a LOT more patience to train an un-neutered dog. They just have a lot more interesting things on their minds.<g> Of course they CAN learn to be reliable competitors, but you have to be prepared for the extra work.
In my case, Kodi's sire is still around and producing wonderful litters. And he's a better dog than Kodi is, based on size if nothing else. There would be absolutely no good reason to have kept him entire, and it would have been more frustrating for both of us. That is all BESIDES the fact that my contract said he had to be neutered.
If I had known more at the time, I would have asked my breeder to allow me to neuter him later (after 1 year) and I am sure this could have been arranged. That's what I will certainly do if and when I get another. But I have no intention of becoming a breeder, so my next puppy will definitely be neutered (or spayed), it's just a matter of timing.