Because the idea evolved out of Jewish beliefs of the scape goat, where one goat carries the sins of the people into the desert while the other is sacrificed to the Jewish god. The idea that Jesus had to die may have come around to explain away why Jesus was crucified. Looking at the Dead Sea scrolls we see that some of the more religious Jews believed the end of the world was nigh, that a battle between good and evil would occur, that two messiahs (one priestly, one warrior) would help lead the battle, that paradise would be restored here on earth, and most importantly, that the dead would be resurrected and judged.
So if your charismatic messianic leader gets killed, what do you do when you really believe in him? To the more practical Jews, he would have just been another failed false messiah. But for the members of the cult who have invested so much time in this man, they must either admit they were wrong, or come up with an explanation.
And this is where cognitive dissonance* kicks in. They believed in resurrection, so come to the conclusion that he died for our sins, and is the first of the resurrected**, marking the end of times. And this is what we see in the New Testament.
For seventy years after Jesus died, they were still waiting for the end of times to begin, within their generation. It's not until the second century that they start to make excuses. Jesus didn't mean this generation.
Or Jesus didn't mean paradise restored on earth but that he would ascend to heaven to be with his father. Or when the doctrine of the trinity was adopted, that he would ascend to heaven to be with himself. See http://en.wikipedia.org/wiki/When_Prophe... Although according to the later gospels, he technically was not the first.
Christ’s sacrifice seems to be an extension of the scapegoat and the biblical practice of offering sacrifices: "But the goat, on which the lot fell to be the scapegoat, shall be presented alive before the LORD, to make an atonement with him, and to let him go for a scapegoat into the wilderness." (Leviticus 16:10) And in Revelation 5:6, John writes "And I beheld, and, lo, in the midst of the throne and of the four beasts, and in the midst of the elders, stood a Lamb as it had been slain, having seven horns and seven eyes, which are the seven Spirits of God sent forth into all the earth.". Although it's a Lamb rather than a Goat, the idea of sacrifice of an animal on whom has been loaded the sin of mankind is there. I suspect that Lamb suggests a purity that a Goat doesn't.
That last point is illustrated in Matthew 25:31 onwards, "When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory: And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats: And he shall set the sheep on his right hand, but the goats on the left.".
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.