IIIIITHE1IIIII on 14 January 2013
"I'm not very interested in Biblical or religious sources of support-"
Well, whether you are interested or not, the answer is in the Bible. The characteristics that you bring up matches the Bible's description of the Creator. If we are talking about people who just believe in "a god", but who does not identify themselves with a specific religion, then the answer is still the Bible - as long as the characteristics are the same.
So, to answer you final question: There is no reasoning. People just follow the old traditions.
