memes is sometime which spreads whether as idea, evolution or jokes.
history, god has been presence for many ages and in many kinds. in jokes, phrases like "oh my god", songs and beliefs and buildings.
therefore, even though science has recently explain the logic of non existence of god, it does not spread quickly and convince people that god does not exist.
there is also commercial profitability and politics of god.
so now we have cultural, psycological, historical, social aspects of god