I said the Bible acknowledges slavery; I said nothing about the acceptability of it.
And I asked that by not speaking against it, doesn't the writer know that he is complicit?
If he gave commandmants to not kill, not have false gods, not envy, not lust, couldn't he have added one more, "one must not own as property another human". How hard is that?
The real answer is that slavery was so common and accepted that the creators of God and the Bible never thought to speak against the system. It was as if slavery was the natural order of events.
The God of the Bible is a realist, my friend.
If only all of his creation were as well...