It was alleged that there were more people accepting biological evolution as reality who accepted God being real, as such being theist. This was contested with a post showing results from a survey showing otherwise.
Those who do accept biological evolution as reality do so because of the wide acceptance of such evolution from natural processes by the scientific community, from the avoidance of so many in that of assuming involvement from God, which they perceive there is no way to study, and so they hold there is no need to acknowledge God.
Without having God to include in what is studied, and to even acknowledge, they take what is left to include in the study of origins, which then is only natural processes, and what is defined for being adequate for explaining what they see being around now is such processes that are ongoing. This includes the natural selection that Darwin noted having an effect on populations, and the mutations from genetic alteration that was learned of later to explain how there would be change from what was defined in gene pools.