Christians are not necessarily stupid. You have to consider the power of indoctrination and fear when applied to little children. I went through the entire Roman Catholic indoctrination mill. It involved a lot of physical and mental abuse by my teachers and a bible thumping, overbearing tyrant of a father. It took me at least fifteen years involving a lot of comparative religious study and introspection to overcome the brainwashing and finally come out as an atheist.
"The world is my country; all of humanity are my brethren; and to do good deeds is my religion." (Thomas Paine)