Evolution is not an issue for most Christians. They have accepted the overwhelming evidence and adapted their theology. Evolution does not require atheism.
Better than that, Saint Augustine in the fifth century, argued that life developed under God's guidance on the basis of his reading of Genesis. He also argued that the universe was created from nothing and that time didn't exist prior to creation.
The idea that all Christians believed in creationism before Darwin came along and proved them wrong is, to use your favourite description, "wilful ignorance" of the facts.
You could argue it took science nearly 1500 years to catch up with Augustine's theological reading of scripture.
A good article on the subject: