Really, why do they? Why is it that they cast their trust in a god that may or may not exist? It must be tough for Christians specifically, because they have to deal with more than a few major problems. For one, our current "Word of God" has been edited; it's not the same book from 2,000 years ago. There could have been numerous little mistranslations. That, and there could have been many additions and subtractions throughout the centuries. Lastly, there are over 20 sects of Christianity alone. Someone must have made a mistake somewhere, and if only one path leads to salvation people aren't gonna be lonely in Hell. How do we know religion isn't truly a tool used to manipulate and control others?
Simply put, religion is a symptom of irrational hope and groundless faith. Another thing I don't understand is why there are religious people in Academia. It makes no sense. In any sort of job that requires a functioning brain you rely on facts, logic, and reason to do it well. As Dean of Medicine you don't have your staff prescribe 3 sessions of prayer every day until the patients are cured. Praying doesn't heal sarcoidoma or neuropathy, etc. There's always an underlining reason(s) for a problem. The part I don't get is why a person with a job that requires rationality... decides to cling to an irrational faith.
Why do they believe? You wouldn't believe that 2 + 2 = 5, so why believe in a God?