You are quite right.

Not only about pets, but this is a pet forum, so will stay on that subject.

Animals have only lately(in the history of living things) adapted or been adapted(chiefly canines and equines) to coexist easily with humans.

There are still examples of feral dogs and wild horses that illustrate how those species were before mankind began selective breeding.

That means different people use different ideas about how to breed, raise, and train both species.

Many trainers make their living by training other folkls animals. Each trainer has to have a lot of very basic knowledge and each develops some special(to them) techniques.

Each successful trainer who is successful develops a following of adherents to their 'system'. Understandable because success begets success. Those adherents believe completely in the system and will defend it almost to the death. The death of friendships or acquaintances anyway.

There is also a huge number of dog(and cat, to some extent) owners who create a human personna for their pets. Calling them their children or babies, assigning human actions to the pet behavior, and in general ignoring the fact the pet is a dog or cat.

That is detrimental to the mental health of the animal, but in many cases, that condition is not dangerous to humans, just the animal.

Some dogs/cats can actually thrive in such situations, by adapting to include the human in the animals family. Small dogs---especially those bred to be lap dogs---often are in those situations. The animals are not abused physically, are well cared for(with the exception of often being overweight) and can live long lives. The majority of those animals(dogs and cats) often display unusual behavior---excessive protection for their owner, OCD traits like tail chasing excessively and so on.

Owners will defend their methods and their treatment vociferously---because the animal fills a very important place in the owners life.

Other folks will just as loudly claim the doting owners are causing great damage to the pets mental state---since dog needs to be treated as other dogs would treat them, not as a human is treated. Stands to reason, when a person is treated like a dog long enough, they start acting like a dog. The reverse is also most certainly true.

Initially, canines/equines were adapted to assist humans with survival. Equines to carry heavy loads and canines to protect and hunt. Those animals even were adapted to help wage war.

As survival for humans got easier, the roles of our companion animals changed. Companionship and even bragging rights became important. Having the fastest horse or the best hunting dog or the cat with the most silky coat became important to a lot of folks.

Changing a dog from one type to another can be done in just a few generations(4-8 years). Those changes are mainly physical---a Great Pyrennes and a chihuahua share over 98% of the exact same genes.. That means that some of instincts formed over tens of thousands of years are still present---in animals that are expected to live in close contact with humans and not exhibit some of the traits inherent because of those instincts.

Puts the animals---and those who try to train them in difficult roles---especially since most dogs and humans are unique individuals and do not learn the same things in the same time or way.