One often sees the following quotation attributed to Seneca the Younger:
“Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful.” Seneca the Younger, Roman Philosopher, 1st century A.D.
Apparently, however, there is reason to believe that he may not have actually written or said those words. The following quotation from Gibbon's "Decline and Fall of the Roman Empire", however, were undoubtedly written by Gibbon:
"The various modes of worship, which prevailed in the Roman world, were all considered by the people, as equally true; by the philosopher, as equally false; and by the magistrate, as equally useful." Edward Gibbon, 1776.
Regardless of who first expressed this idea, it is one often expressed these days on the internet and in other media. I think it is so often repeated because so many people realize just how true it is and how succinctly it sums up a complicated situation.
One of the notions contained in this expression is the idea that the world is not divided up into believers and non-believers only. There is at least one other class of persons who take an entirely different view of religion. These are the ones I have mentioned before who are primarily interested in power rather than truth. Such people may or may not actually believe in the truth of religion or some part of religion, but they do not usually reveal the truth of their actual beliefs to others. They may not even know with certainty themselves what they believe.
Such people apparently see the world in a way that is difficult for believers and non-believers alike to truly grasp. The truth or falsehood of religion is simply not important to them. What is important to them is power and the means to achieve it.
It can be argued that Hitler belonged, partially, to this third category of people who are at least as concerned with the usefulness of religion to them personally as they are with the truth or falsehood of the matter. But, it is clear that he was not an atheist.
The material to be found at this website make clear that Hitler's rejection of the current Christian churches was not based on atheism. The material also makes quite clear that the lie being spread by numerous Christians in recent years that Hitler (or the Nazis) were atheists is patently false. (As does the material on this website and those to which it provides links.) See ftnt.
Among the many original documents reviewed and included in the first website is a voter guide distributed to Catholic voters in Germany before the vote on Nov. 12, 1933, telling them that they must vote for Hitler and his supporters. Also included is a portion of a document prepared by a Nazi committee in 1943 and presented to Hitler outlining a plan to proclaim Hitler as the "new Messiah" after the war was "won".
This plan to replace Christianity is one of the reasons that so many Christians try to argue that Hitler was an atheist. Obviously, however, this plan is consistent with what I mentioned before: Hitler saw himself as the instrument of god. He believed that Jesus was actually the illegitimate son of a Roman soldier (and therefore not completely Jewish) and that the Christian Church was the creation of a Jew--Saint Paul, otherwise known as Saul of Tarsus. He thought of himself as the instrument of god sent to "correct" Saint Paul.
He appeared to think that Jesus' message had been garbled by a Jewish conspiracy--which is the way he saw the rest of the world as well. He was certain, like most religious people, that god saw things the same way he did and that those who disagreed were just wrong about god's wishes. This tendency to "personalize" the religious delusion exposes it as the personal delusion it is.
"[Y]ou can safely assume you’ve created God in your own image when it turns out God hates all the same people you do.” -Anne Lamott from Bird by Bird.
Footnote: This web page also contains numerous links to materials de-bunking the "Hitler was an atheist" lie. A related web page contains pictures of numerous artifacts showing that Nazis were Christians. At the bottom of the page are three paintings by Hitler--one of which is of the Virgin Mary and Jesus as a child. That particular painting is very strong evidence of Hitler's continued belief in Jesus. The owner of the page suggests that non-believers use the painting as a Christmas card to send to any believer who claims Hitler wasn't a Christian. The suggestion is humorous, but be careful not to feed the lie that we atheists are Nazis if you do such a thing.