We all have inherited, some to a higher degree than others, cognitive dissonance, the mental discomfort and psychological stress experienced by a person who simultaneously is facing two or more contradictory values, ideas or beliefs. To offset these feelings, we also all have, to some degree, the mental capacity for delusions, a mistaken belief that is held with strong conviction even when presented with superior evidence to the contrary. This also was probably a helpful trait during evolution since it is so widely spread. If a delusion, however is very strong it becomes a problem (see the symptoms as published by the APA)
Before science, a very, very recent development in our history, gradually showed us the reality of nature step by step, the need for believing in these fictional entities and the delusions that convinced people of their authenticity gradually decreased but the resistance to give up these comfortable myths is still very strong because of our genetic make-up, which changes at a slow evolutionary speed rather than the exponential speed that science is developing.
Science was developing at a slow speed before writing was invented and communication between generations was often by story-telling and very inaccurate. When writing was developed it became easier to transmit information from generation to the next one, but so were mistaken ideas. It must be remembered that writing was limited only to a few elites, and that even a couple of hundred years ago over 90% of the population was illiterate. Christian Church services in the middle ages were in Latin, a language that most people did not understand, and thus had to rely on the clergy for explanations, which could be consisting of very personal opinions. This gave the clergy, total unquestionable authority which was often cruelly enforced.
Only in the last few generations has general literacy been established. Science has now become available for the masses and flies in the face of our inherited delusional beliefs. Cognitive dissonance also is playing a big role. Depending on how strong these traits are in a person, science is often difficult to accept and replace beliefs, therefor pseudo-science is rampant, to counteract the mental discomfort of many people, when real science confronts their illogical beliefs.
We cannot wait for slow evolution to override the inherited tendencies, but education can do the trick and overcome our primitive instincts, as we have done with other ones, to some extent, although not completely erased, such as rape and murder.
Since different religions in the world often create great conflicts, even between factions of the same religion, it is imperative that we built a secular world society, governed in a democratic way without the influence of non-elected religious leaders or other ideological rulers who influence current governments in many parts of the world today.