It's because the religious dogma preaches to the uneducated ignorant and it is also why these same religions fight education. For when ignorance dies so do religions.
http://www.npr.org/blogs/13.7/2012/01/18/145338804/why-do-so-many-have-trouble-with-evolution?ft=3&f=111787346&sc=nl&cc=es-20120122
