Yes, many in the South did claim and still claim that their discrimination against Black people was/is Bible based.  I don't know what they cite - in part because I never even tried to get in a Bible verse back and forth with a Biblical literalist - useless.  Equally, true I would have lost any such battle since my religious upbringing  didn't include memorization of vast sections of the Bible.  I was raised on Catholic catechism and good manners.   

I think a modern society has to have some rules about how far someone with strongly held religious beliefs can go in expressing those beliefs when that impinges on the freedoms of others.  And that includes how far bosses can go in a business that serves the public and hires people of different/no religious faith.  Think health insurance and LGBT marriage. 

How to reconcile fundamentalism with individual freedom and opportunity is what we are trying to figure out.