My God really? Slavery was the uniform norm for almost all of human history [0]. If nothing good can come of a society that enslaved others, then the logical corollary is an incredibly short sighted and unnecessarily nihilistic view of the journey of humanity. Can we give history a break?
[0] https://upload.wikimedia.org/wikipedia/commons/thumb/9/92/Sl...
Edit: before somebody says blah blah race, there isn't a race on Earth that wasn't subjected to slavery in history.