I'm curious -- is it stated anywhere in Freemasonry why atheists are prohibited?
The general thinking is that if a man can declare without reservation there is no diety, or God, or Supreme Being, or <fill in your favorite god-noun here> then this man already knows everything there is to know. What can someone like this be taught? Such immediate signs of vanity and arrogances should not be ignored in selecting possible brothers. Masons go for quality over quanity.
Not sure what the exact verbage is or where in the charter it is mentioned. Interesting question though.
I know that during the initial interviews, the entering apprentice is asked if they believe in a supreme being and they just let it go at that. They are not asked "which" supreme being or what religion or denomination they believe in. It's nobody's business. I have seen Masons wearing various jewelry with crosses to pentagrams, catholic saints, Wiccan symbols, hierogliphics (sp?) among many other symbols. I can't say it reflected their spiritual beliefs or not because I never asked. None of my business. You can believe in the Flying Speghetti Monster, I suppose. As long as you believe in something. They never ask. It's none of their business. That is for the churches to hash out. That is between a man and his preferred diety.
In lodge, they always open with the "blessing of diety." The "diety" is referred as The Great Architech of the Universe. It is a generic name to mean "whatever diety you personally believe in" so as to be neither conclusive or inconclusive to any particular belief.
What political persuasion a man follows is never questioned as politics are never discussed and are considered taboo conversation within the lodge. Let politician's be politicians and preachers be preachers. That's their thing. Not ours.
Masons are just a bunch of regular guys who meet every so often, have a good time, and go out and collectively do something good for society. Plus, we are obligated to conduct ourselves the best we know how. You have to be a Master Mason before you become a Shriner. Masons and Shriners give millions of dollars a day to help children of all walks of life. They may show up one Saturday morning to build a ramp for your wheelchair bound granny. It's all about doing good.
Like any organization, it can be infiltrated by cowens and eavesdroppers I suppose. But it is fun reading all the rediculous conspiracy theories from the tin hat people. We do get a kick out of it.