I'm curious as to how you can think any ethic, especially the Judeo-Christian ethic, can be based on a man who was deluded in thinking he was the Son of God, the promised Messiah of prophecy?
In Mere Christianity, C. S. Lewis writes this about Jesus:
"I am trying to prevent anyone saying the really foolish thing that people often say about Him: "I am ready to accept Jesus as the great moral teacher, but I don't accept His claim to be God." That is the one thing we must not say. A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic - on a level with the man who says he is a boiled egg - or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God: or else a madman or something worse. You can shut Him up for a fool, you can spit at Him and kill Him as demon; or you can fall at His feet and call Him Lord and God. But let us not come with any patronizing nonsense about His being a great human teacher. He has not left that open to us."
It's not until the "gospels", written in a largely Hellenistic vein some 40-60 years later, where but for Roman "coin trading" one might otherwise think the Jews were in charge, do we hear otherwise.
Though as I've said, Thank God for it, as we Americans most likely would not be here without that having happened.