I think you are arguing with yourself. You are rehashing simplistic ideas, which I agree with, but not placing them in the context of reality. It is fine for you to sit here now, today, and insist that slavery is wrong and immoral. Gee, I wonder what people majority of people thought (religious or not) during the last 200 year stint of slavery (being the most recent of many such long drawn examples)? You think you are smarter than them? You are only benefiting from 20-20 hindsight vision, which is why it looks so clearly wrong to you.

Christians are immoral for doing good deeds in hopes of a reward of going to heaven or fear of going to hell. That makes them less moral than people who are atheist but do the right thing for the simple fact that it's the right thing to do.

I have no clue what you are driving at here. Perhaps you should go debate that issue with a member of the christian religion. But I will point out that the simple facts have changed repeatedly over time. Back then, being a good master was the simple fact.

Let's end this here. My simple point is that you are assuming you know what is right and what is wrong, which makes you no different than men during every other time period.