Why do atheist people think they are smarter than everybody else?

Answer 1

They're not. They just have a different perspective on creation and life. Unfortunately this causes conflict with people who believe they have all the answers through their own personal belief system, religious or otherwise. There are many unanswered questions about life and the universe its just that atheists tend to approach the subject a little more scientifically.

Answer 2

Most groups feel they are more intelligent than groups that don't agree with them. In the case of Atheists vs Theists the definition of "smarter" is difficult to quantify or define. That said, data indicates the the more education a person has the more likely they are to be atheists or at least secular in their outlook. This applies to countries as well as individuals as countries with higher levels of education are found to be more Atheist or secular. Similarly the earning levels of Atheists (on average) is higher than Theists. Other studies assert that the IQ levels of the two groups are comparable.