The writer seems to say this in order to plant the idea in the readers mind that the natives could easily be shown god and become religious, however he later explains how even though they could be molded and they would be docile they were still slaughtered, it seems for no reason other than differences in power and desire for land.

This comment where he says that he wished they were treated like beasts stands to show the horrible extent of how they were treated because he wished they were treated "as good" (compared to how they were treated) as enemies or beasts because they were treated like literal waste and filth. He tries to explain that the natives never did anything even remotely harmful or rude to them to inspire this treatment and even when they were being treated lesser than objects they still didnt replicate the behavior that the Europeans were showing them. They only fought back when it was their last resort of life.

The Christians arriving on the natives lands betrayed their own principles when they exterminated 80% of the natives and treated them lesser than objects

The king tried to protect his people by saying they were harmless however cortes was ruthless and slaughtered them regardless.

Cortes all along was planning on attacking and slaughtering the whole city in order to capture it. He did this by becoming friends with the king and gaining his trust then attacking all of is people while they were in celebration and not armed. Cortes had to do this in order to conquer this city because it was so strong and powerful and booming and he knew that in order to conquer it he had to get inside the walls without being attacked and conquer it from the inside out

The king of Tenochtitlan and the incoming Spanish are having a friendly conversation showing no hatred or fear or longing to conquer. The king even treats the Spanish as gods coming to their land and praises them.

He is already talking about them as if they are his slave (objects) that he can do whatever he wants with even though he is writing after friendly encounters and has not captured them.

This is the second time he has compared the natives to horses (animals). This shows that he thought of them more of objects than humans and that they could be tamed. It shows innocence and willingness to be controlled.

Directly stating here that they would be easy to capture and make good slaves. This created the idea that the natives were only there to help them and be their slaves. Since he earlier talked about their skin color being darker than white it also symbolizes the start of the African slave trade and how slave trade had more to do with color and race than convenience and kin.

Again shows that they are weak and innocent. They know nothing about war and show no threat to the europeans. This shows the europeans how easily they can be conquered and presents them as weak peoples.

This shows how easily bought the natives were which represents how they can be easily manipulated with little effort or money. This represents to the europeans that the natives might be weak/not a threat and could be easily taken over.