The early church was strongly against slavery, on the basis of the scriptures: given that every human is in the image of God, then claiming to own another person is blasphemous; and given that the blood of God Incarnate was shed for every person, claiming to own another person is even more blasphemous. With those conclusions, the claim that “the Bible condones chattel slavery” is erroneous – it rests on a “recipe book” approach to the scriptures rather than taking them as a whole.
The Bible is against slavery when you look at the principles instead of treating it as a menu book where you get to pick what you want.
Because opposition to religion is a pack of inconsistent self-serving falsehoods that has been consistently detrimental to those societies that most embrace it, and has been used throughout history to justify and cover up everything from racism to racketeering to slavery to child abuse to genocide.
Similar things can be said for so many things… fire, drugs, metal, science, books, logic, words, merchants, …
It is the problem inherent with everything with power – that power can be used for both good and evil.
Religion is dangerous. I say this a lot. But there are many things which are more dangerous. By all means avoid them if you cannot handle them or cannot control yourself. And one of the things which is far more dangerous are religions (and other things) which are unaware of the danger of religion (or those other things). And that is not true of Christianity. I who was raise from childhood with abundant criticism of Christianity was quite surprised to find those same criticisms right there in the Bible. This is a religion which is very aware of the dangers of religion.