Why can't dead people in heaven talk to people on Earth. Nothing would put a person on the straight and narrow for Christ faster than a talk with their dead grandmother in heaven. It's no more compulsory than a talk with a living grandmother. But, oh so much better. Why then is there no communications?
Given Christianity this would serve God's purposes, ad hoc reasons must be given as they are pulled from one's ass.
Given atheism the answer is obvious (dead people are dead).
So atheism provides what amounts to a free explained phenomenon simply as a side effect. But, Christianity needs to make up something new to explain that problem.
This is evidence for atheism and evidence against Christianity.