Added Later
I just saw this discussion between Richard Dawkins and Ayaan Hirsi Ali
which encapsulates what I earlier wrote better than I did:
14 min:
Dawkins: Christianity is obsessed with sin
Ali: Christianity is obsessed with love
Towards the end
Dawkins: I want the truth
Ali: I want redemption
Ali's closing note: Humanism took away Christianity. The vacuum was filled by the violence of Islamism. What are you offering when you take away Christianity? Humanism has clearly not worked...
Dawkins: You want to cure a virulent virus by vaccinating with a milder virus, I want no virus
It's very clear that they are not disagreeing but talking at very different levels