I recently read an interesting article from John Shore about the discussion between an Christian and an Atheist on the topic of Hell guess who won the argument the Atheist and to be fair trying to defend the concept of eternal torment with an god who claims to be the source of all love is wisdom is I find to be impossible.
http://www.patheos.com/blogs/johnshore/2013/12/atheist-and-christian-argue-about-hell-in-a-starbucks-atheist-wins/
Yup, the concept of Hell turns multitudes away from the church, Christianity, and God - all so that the True Believer can take comfort in others getting their just desserts, and the T.B., not.
Not just the concept of hell but also the Nicolaitanian attitude of the church.
Not to speak about the flat earth theory they held for a long time.
I think it's are several things that add up.