Because they want to.
To be vulnerable is needed most of all, if you intend to truly fall apart.

Quote by due 07
You have no idea how much I don't want to tell stories about my mother's vaginal slime on the internet.

I make music sometimes.
I agree with you that the divine exists and evidence for that existence is all around us, but there are plenty of reasons why someone might be an atheist. Believing is hard sometimes, that is why we must have faith. We have to see that many people simply cannot bring themselves to believe in God.