Basically because when someone's ideal is threatened they will reach for the lowest common area of uncertainty and try to endue doubt to make their proposition at least feasible, and for now the concept of god is at least feasible compared to other hypothesis of origin, that is to say there is nothing empirical to differentiate the hypothesis from each other and thus no reason to favour a single explanation. People who favour the idea of god do so for non-smart reasons, such as an appeal to emotion or an argument from ignorance.
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