Paul
Atheism is not a belief system. Atheists are usually people who although have been brought up in religious families or societies, have not accepted everything they are told about religion. They had the opportunity to look at other points of views through education. They have reached the conclusion therefore, that there is no objective evidence for the existance of God, and the holy Books of any kind, are the myths and stories of a group of people in a corner of this planet which have been taken as truth by the majority of people.

I don't think atheists are exclusive. I also disagree with the notion that most of the people with average intelligence cannot be atheists. It is not the matter of intelligence. It is the matter of adequate education and presenting all the scientific evidence and viewpoints to people. Indeed the distribution of the adequate education is very poor in general in the world.

For example, in my country, Iran, neither Big Bang nor evolution in being taught to children in school. There is no doubt that the majority of these children who do not have all facts will grow up to believe whatever the clergy tell them. There are people like me who mostly because of their families and because of getting exposed to books and education more than the formal education become atheists or agnostics.

I am positive if others had as many opportunities as I and my friends had, they would not have accepted the whole religion package so blindly. Unfortunaely, education is not adequate and the wealth is not distributed equally so that every child can have access to scientific knowledge.