I am perhaps a romantic but I must attribute my highly suspect idea as to how it (religion) started to awe and wonder and I attribute human sacrifice, et. al. to the cynical evil in us that seeks advantage by controling our fellows. At base we are perhaps saying at least similar thing.
I used the Aztec human sacrifice story to show how religion is in reality a human tool per those that advocate this theory. Once the tool was shown to not work the religion or ritual is dropped and man seeks a better tool. Like dropping flint tools for bronze.