Freemasonry is not a religion. True they do require all their members to believe in a supreme being, so yes they do discriminate based on belief and that is wrong, but they do have Christian, Jew and Muslim members. They have done a lot of charitable work and we cannot overlook that just because they are unfair to atheists.
It's true that they have many charities, but that doesn't mean they're not an occult. Cults have charities. I bet even satanists have charities, as in The Church of Satan. Did you know the Church of Satan is a 502(c)3 organization?
It's true Freemasons have Christians, Jews and Muslims....but as a mason graduates through the degrees, more is revealed to him about the nature of their deities.
I do no know if they're unfair to atheists more than they're unfair to anyone else. If a group will not have me on the basis of my beliefs, I think that is fair enough. To a Freemason, we are the profane. That's fine by me. I do not care what crypto-satanists think of me.