In the beginning, humans were hunter-gatherers. They didn't affect the ecosystem on a large scale. They were animists (Animism is the belief that objects, places, and creatures all possess a distinct spiritual essence). The world was a stage for everyone to perform. Humans were not the only actors. Every being had a story with value that deserved respect.

Then they became agriculturists, which brought wheat and religion. Now, the world became a stage for humans and gods (sanctified). Agreements and arrangements made humans the masters, allowing them to act at their will. They only needed to answer to god for any kind of exploitation. Other species were seen as existing solely for their benefit.

Why was domestication harmful to animals?
Because it interfered with their ancestral needs and disrupted the evolutionary modifications of millions of years, causing them to suffer.

Organisms are algorithms (stimuli as input, neuron firing as decision-making, and organs taking actions). Referring to animals as mere algorithms to justify their exploitation makes no sense, as humans themselves surpass such boundaries. If we reduce animals to algorithms, we could also dehumanize humans, as has happened historically in cases like slavery, invasions, and death sentences.

The Scientific Revolution made the world a stage solely for humans, with no gods. Now, the cosmos was judged according to what was good or bad for Homo sapiens. Humanist religions came into existence, such as liberalism, communism, and Nazism.