Misconceptions about the Bible

[Data]

Both magic books were written by people with different views than our own on slavery.

Excellent point. I would only add that the earth was given to mankind acting as steward temporarily meaning that he can do pretty much whatever he wants. If he says slavery is or isn't acceptable then that's his business, though, for Israelites and Christians there were laws regarding the proper treatment of slaves. For example, kidnapping a person to be or be sold as a slave was a capital offense. Hebrew slaves were equal and free to have their own wealth, business, etc. Even in Egypt Joseph as a slave was the second most rich and powerful person in the nation. A person could volunteer as a lifetime slave, or sell themselves temporarily as a slave to pay off a debt or theft. The non-Hebrew slave was pretty much a prisoner of war with less rights but still protected to some extent. Hebrew slaves were released, with a compensation to start them out on their own after 7 years of the 50 year jubilee, whichever came first. 

It's not really surprising that we end up with paul telling slaves to be obedient to their earthly masters as to christ.

 
Not surprising at all given that that was the law at the time. 

The issue repeats itself with big mos magic book.  Where, since slavery is present and acceptable, the best we can say is that they (all three magic books) progressively reformed and regulated an institution which they didn't fundamentally question.

  
Again, yes, due, in part, to the laws of the time.