The same Paul who wrote the passages you complain of writes in 1 Corinthians 7:21-24,

"Were you a bondservant when called? Do not be concerned about it. (But if you can gain your freedom, avail yourself of the opportunity.) For he who was called in the Lord as a bondservant is a freedman of the Lord. Likewise he who was free when called is a bondservant of Christ. You were bought with a price; do not become bondservants of men..."

So the same Paul does recognise slavery is not an ideal and beats you to the punch in encouraging slaves to seek freedom.

Secondly, you say the Bible did not teach anything extraordinary on slavery but it did teach that men are CREATED in the image of God, an extraordinary idea that led Christians to abolish slavery which was just standard human practise for thousands of years.

So slavery was abolished on Christian grounds, we are all created in God's image. Question for you,

On what grounds could slavery be abolished in an atheistic framework? And secondly, can you, based solely on atheism articulate why slavery is "evil"?