“Please. Explain to me how slavery can be considered a compassionate institution by any definition of the word. I really, really want to know.”
Again, equality spoke only to the origins of the institution being founded of compassion and left the moral conclusion to the reader. The question to which you seek an answer is a question each must answer for himself.
How is supplying a market for raiders to go deep into Africa and capture people for sale “compassionate”?
People wanted slaves. Slave markets rose up in response to this. Southern plantation owners didn’t win a war over African natives. They just paid for others to kidnap them so they could buy them.
Again, what possible evidence is there of slavery beginning as an altruistic act? Slavery, from the moment it began, was a barbaric act of one person oppressing another. There is not, and never has been, any compassion in it at all.