If I may, I believe have a answer as to one of the "WHY
" questions. To......
"Do unto others as you would have them do to you."
And I think it's just that simple. Also the phrase is probably in every ancient religious text of the many different religions, but worded differently, with the same meaning in mind. (I know I've seen it in Confucianism and Zoroastrianism texts, which predates Christianity.)
But I really believe you could worship anybody or anything (or not) and it wouldn't really matter as long as you follow that little golden rule; which does serve a useful purpose.
It seems to me as though many different religions have come and went over the thousands of years that have passed, but that simple moral rule remained constant and probably because it's a eternal universal truth IMO.