Burn,
Maybe because some of us do not think these others are not entirely made up? That statement is fraught with assumptions with respect to the truth value of other religions.
Yes, I understand what you are saying, but the reality is that without a human component there would be no religion. It is only on the basis of human interaction that a religion becomes. Any universal truth, if it exists and I doubt it very much, is filtered through individual human chemistry.
Though people may think they believe in the same God, they imbue their 'God' with elements of their own personna.
In order for your statement not be be fraught with assumptions, you would need to show a universal spiritual truth that exists outside of human parameters, and I very much doubt that you can do that.
People make God in their own image. This has been so since the dawn of human consciousness. I once suggested that you read 'A History Of Religious Ideas' by Mircea Eliade and I recommend it to you again. It traces the primitive instinct and need of religion from its embryonic first growth until its fully fledged modern development. In this process ones never sees God, one only sees man trying to build the God he needs from his own insecurities.
HS