Why Are There Atheists?

Have been reviewing my Kindle bookmarks just now.  Don't remember underlining this but in a short booklet on Thomas Aquinas this jumped out at me.

Thomas Aquinas in 50 Pages: A Layman's Quick Guide to Thomism (Taylor Marshall)
- Highlight Loc. 484-85 | Added on Friday, October 30, 2015, 12:15 PM

Usually, atheists or heretics are what they are because of scandal and moral scruples, not because of logical failures.

Have forgotten the context for this.  I recall in the early part of one of Brian McLaren's books, I think Generous Orthodoxy, he says that many of the liberal christians he has met are former fundamentalists or conservatives who've been through bad experiences.