Members of the Reichstag salute Hitler at the Kroll Opera House on 6 October 1939, at the end of the campaign against Poland (Photo credit: Wikipedia)
Religion intentionally divides people, typically through generating superficial differences such as which clothing one wears or what eating & drinking habits one has, because religion relies heavily on the “us vs them” mentality to thrive. Indeed, religion is the origin -the original source- of discrimination, racism and fascism alike. It was the first successful attempt at politically consolidating hatred against outsiders, or really anyone who was perceived to be different or deviant from the religious majority.
The far-right and Nazism later on “perfected” this mentality created by religion, culminating in the Holocaust. Indeed, every Nazi soldier had the words “God with us” engraved on his belt, and Adolf Hitler was well-known to speak very highly of Islam. These are not merely unfortunate coincidences.
Religion is the quintessential capitalist undertaking. It sells an inherently ephemeral product that can’t be quality tested. Most of the value of that product exists only in the minds of the purchasers, and most of that value cannot be realized until death. Dissatisfied customers cannot return the purchased wares to the undertakers who sold them. Aside from a fancy building, very little in the way of productive facilities is actually required by the religious undertaker
It’s not so much about religion, but human nature. Humans are not as rational as rationalists like to think they are. Instead, humans are very much affected by instincts, emotions and intuitions. Reason is of course available, but too often used to rationalize instead of for reasoning.
And all of us are non-rational–atheists as well as theists. Atheists try to be rational but often fail to recognize their own non-rationality, while theists often delude themselves in other ways