Are all these breeding standards actually a good thing?

I agree with you whole-heartedly, that is why these days I get so sad when I see the dogs with the short legs like bulldogs who can hardly breathe or rhodesian ridgebacks that are culled(sometimes killed, sometimes sold spayed and neutered as pets) because they don't have a ridge that is why we stress the importance of pet adoption because if you don't buy then the practices will have to stop.

and how does breeding obvious defects into the lines improove it?

If it has health issues.. cull it

temperment issues.. cull it

any trait that deviates away from the dogs standard or purpose.. cull it. There's a reason why certain traits are undesired.. some are linked to health issues, and soe deviate away from the purpose of the breed.

smaller gene pool does not always mean a higher risk of defects.. not if one has taken the time to study the pedigrees and knows what is in those bloodlines. If there's no defects within a bloodline, then you wont produce defects.

Most breeds have a broad enough gene pool, even among reputable breeders, that they are not so limited to worry about health issue.

Species can recover from genetic bottlenecking.

Dog breeds are being kept alive and healthy by careful genetic mapping and planning. It would be almost impossible to create a genetic bottleneck in a popular breed, like Golden Retrievers, or even an international breed, such as Basenji. Adding to the gene pool does not mean genetic mutations disappear, just as breeding a Poodle to a Labrador Retriever does not mean the puppies will not have inherited PRA from the Poodle parent or hip dysplasia from the Labrador parent. In fact, the litter could have both genetic disorders if the parents have the alleles.

Here is your logical fallacy: that the remaining dogs MUST carry defective genes that result in genetic health problems. That is simply not biologically true. Small gene pool does not equal health problems, it only reveals what is already there (if a small gene pool was a death sentence then no one would still be alive in Iceland). You can start with two mice and breed sibling-sibling for a hundred generations without seeing any increase in genetic disease or any novel genetic diseases that were no already present. There was also a recent study that the children of first cousins tend to be the healthiest, on average, compared to all other possible combinations of parents.

Why should I keep dogs in the gene pool that are not functional or that I KNOW carry genetic diseases? I should subject 1/4 of the breed population to progressive retinal atrophy because if I remove those animals I *might* have different problems later? And in the case of recessive genes, it is a normal, acceptable, and ethical practice to breed carriers so long as you only breed to non-carriers (so you KNOW you will not produce effected puppies) and test the offspring so you can, again, never breed carrier-carrier and produce effected pups.

Without removing dogs from the gene pool and continuously guarding breed type, we would soon regress into generic dogs. These dogs would be OK but not great at most jobs, and entirely unsuitable for specialized jobs. We would be unable to predict which matings would producing the working dogs that we needed and would end up having to produce two or ten or a hundred dogs to get ONE working dog that we needed - the end result would be hundreds of surplus, unsuitable dogs, many with health problems since those genes were left in the genetic pool - and what happens to all of them?

I'll stick to my line-bred, predictable, healthy, well-bred purebreds, thanks! If you want a dog with "diverse" genetics there are a few million in US shelters that would love to be your new pet.

The point of breeding is to improve on the breed.