Actually The Lord of the Rings is an allegory based on Biblical themes, not the other way around.

Nobody else is sinless so nobody else could offer themselves as a substitute since they would already be doomed by their own sins. Jesus had to first live a sinless life before he was qualified to be the Lamb of God.

The reason he doesn't just forgive everybody is because there needs to be repentance and admission of the need to be saved. Quite frankly, he wants to eliminate people with attitudes like yours. So the things that the world finds foolish are the very things that separate the sheep from the goats. Until you appreciate the kind of love that would do that for people who don't deserve it, you do not yet have the attitude that will allow God to ignore what you (and I) have done.

Given these facts, the only fatal sin is rejecting God's help out of arrogance or unbelief or desire to be in charge of your own life.

As for slaves, I have told you already. It wasn't on Jesus' agenda at the time and that's His choice to make.

Now come on, really, given all the things you have done wrong in your life do you really presume to lecture the Lord Jesus on what His priorities should have been? And are you holding out on Him because He doesn't meet your standards?

Sadly, that is the state of Man and why God needs to have a simple filter to separate that attitude from the attitude God intends to save as members of His family for all eternity.

"Seek the Lord while He may be found."