A lot of people, especially the tech crowd, have been taught in undergrad the importance of critical thinking and evidence supported conclusions. Also, I think the science/mathematical mind is drawn to this line of thinking as well, which is understandable. I know extremely well how they feel, as I've always operated the same way.

That is why faith in some kind of God or afterlife goes against everything we in the tech crowd are trained to do. The hardest thing about being a Christian or believing in an afterlife IMO is the faith aspect itself.