How Do You Respond To An Atheist With This Objection?

[Guest]

The historical context forms the perspective of the author. The author is not a robot, and he does not go into a trance with God guiding the pen and writing the words for him. The Church does not accept those as valid modes of transmission (I'm not saying anyone here is claiming that specifically, but this idea seems to always be an undercurrent... it's hard to avoid when we are thinking about the nature of inspiration.) The author is truly and fully human, with free will and his own intellect. All authors of scripture have a bias that is formed by the culture he lives in. Bias is not a bad thing, it just is. We are who we are. God is one at all times, yet not all human beings understand him the same way. Ancient cultures had ways of understanding God that we do not share now. 
For one thing, we have the wonderful revelation of Christ's life. 

Can we accept the human perspective of the author, and still give our assent to the absolutely inspired nature of scripture? Yes we can, through faith and the guidance of the Church. Faith asks us to read and absorb scripture, pray over it, listen to the Church, and above all accept it in light of the person of Jesus Christ. 
All scripture is a work of literature, but scripture is not literalist in the eyes of the Church. Not all scripture is factually and historically provable, or "true". And yet it is all Truth. 
Literalist interpretation of scripture is dangerous. It can be used to justify all kinds of evil in the name of "God's will" and it has used this way over the centuries to this very day. 
A Catholic is not required to accept that God literally willed the slaying of seemingly innocent people by others. It is ok for us to believe that the author had an understanding of God's will that is influenced by the times and place he lived in. 
But a Catholic is required to accept the inspiration of these passages and the Truth they convey. And this is why we have exhaustive study of Scripture in the Church, that the Truth might be expressed.