Firstly, Jesus sacrificed himself so people on earth would have a way to get to heaven. He sacrificed himself so that we, as humans, would never have to sacrifice animals or others in order to be forgiven of our sins. Him, being the shepherd, sacrificed himself for his sheep (us.)
Secondly, CN is a game. Conflicts and things are what makes it entertaining. If we all did things that you said then we could close down the game and sit around in a circle holding hands. This game is build for war (NUKES!) and diplomacy to take place.
Another little tidbit for you is that not everyone believes in Christ, Christianity, or anything similar. So, people aren't going to car what Jesus did because it doesn't affect me at all. By us imposing our Christian morals over others, against their will, will cause their hatred to grow even more just for that fact.