Once Muslims understand how sorely they have been deceived by a cult that is a
matter of fact epic failure in terms of scripture, history, archaeology and geography, many of them are then so disgusted for having believed in Muhammad's flying donkey-mules, talking ants and birds, that they associate that nonsense with religion and so sometimes first turn to atheism, as a first step down the road to understanding the love of the one true God of the Jews and Christians, as He revealed Himself through all of the prophets and witnesses, of His 1600 year record.
Exmuslim mostly atheists here
http://www.faithfreedom.org/Pat Condell - anti-religion in general but has a particular talent for crafting anti-islam messages
http://www.youtube.com/user/patcondellhttp://www.councilofexmuslims.com/http://exmuslim.org/