While reading your article, I couldn’t help but think of how the U.S. conducted eugenics experiments and had eugenics policies during the early 1900’s for people. The same reasoning pertaining to animals was brought into play for humans, as the human eugenics philosophy and era came out of livestock breeding. Eugenics reasoning is flawed, although some aspects may be helpful towards understanding traits, such as that used for dog shepherds in police work. Overall, I am glad those days of eugenics are over, and think that the ideas of value for certain jobs in the animal world today could be dialed back a bit. Eugenics for humans and beasts is not foolproof or even workable in the big picture.
Having said all of this, I am not against breeding animals for specific physical and emotional traits…not people. Some breeds of animals have shown up spontaneously having very obvious personality and emotional traits. People have noted these breeds and kept them going, along with specifically creating other breeds, for their temperaments as companion animals. To me, this is a bit different than breeding animals (or people) to do certain jobs, although being a companion animal can be considered a loose kind of job. Keeping certain physical and emotional traits around is not a bad idea. The designation of jobs for certain traits is where illogic is introduced. Whereas specific breeding works a lot of the time, it is not true it will work consistently. Personality is part of the picture and is the one trait that cannot be reliably bred. Differing personalities occur across all breeds all the time. And, differing personalities are more prone to be harmonious with differing jobs. We see that this is true with people.
As a former cat breeder, I can say that my breed of cat was known to be wonderful as a companion animal. Nevertheless, my cats had a whole array of personalities, none bad. But, some cats were more apt to want to cuddle in cetain ways than others. None of my cats were exactly alike because they had different personalities. One works with the personalities, and not all personalities are fit for certain jobs, if an animal is going to be a working animal. Additionally, this is not to mention mental illness. Mental illness occurs across the spectrum of animals and people, and has nothing to do with “breed” traits. I had a few cats who were mentally ill.
Perhaps personality and mental illness is why specifically breeding people for certain traits fell out of favor. When breeding is for traits, the traits will be there, but the personalities and mental illness override the traits.