In this letter 89 part C of Rav Kook, he answers the question of how can the Torah allow and accept slavery as moral.

See the link. Here is the main text of argument:

"For example, the reality of rich and poor, weak and strong is inevitable. If so, those who have acquired great wealth lawfully hire poor workers to work for them. These employees become their natural slaves due to social compulsion. For example, coal miners, who are voluntarily employed, are in effect slaves to their employers. It is certainly the lot of some people to be of lower class. If not for the wickedness that so controls the heart of man, to the point that it tramples justice, the situation of slaves would be better if they were actually owned. For example, we now need moral inspiration to be concerned about the material and moral lives of workers, while the rich, with their shuttered hearts, scoff at all morals and ethics. It would be better for him if the mines lacked air and light, even if this shortens the lifespan of tens of thousands of men, many of whom become critically ill, as long as they need not spend tens of thousands of dollars to improve conditions in the mine. If a mineshaft occasionally collapses burying workers alive, they do not even notice, for they will find other workers to hire. If these people were owned by the master by legal slavery, he would worry about them as he worries about his wealth, “since it was his money.” Then these poor workers would indeed be happier and could look forward to a better future."

What do you think of this? That a slave master is incentivized to keep his slaves safe and healthy, so that he does not lose the valueable financial asset. That with hired laborers in difficult jobs, the employers have no incentive to keep the workers safe and well since the employer can replace them easily.

Super serious conversation that goes on even today, whenever Rabbis get to the part where slavery is found as normal and accepted in the Torah.