> Christians start saying that those bits don't count, or those bits have been misinterpreted, or that you need to read that other bit as well.
When it comes to the diverse views among Christians, here are two things to consider:
1) St. Paul in the NT says "hold fast to the traditions you have been taught, whether by word or by letter." This indicates, along with historical evidence, that a substantial body of Christian teaching lies _outside_ of the written documents of the New Testament. In as much as some people try to use "the Bible alone," we can see that this results in a tremendous amount of conflicting teachings. It's of note that the New Testament did not even exist in a definitive compiled form until a few hundred years into the history of the Christian Church.
2) Ultimately, for Christians the Word of God is a person, not a book. The God-man Christ did not issue a new set of laws, but took on flesh and taught by example how to live. The Christian is concerned with understanding this Person, and people are much more difficult to describe than laws.
So for the Christian, while the Bible is of course an important guide, it does not represent the totality of Christian teaching. And since this teaching is about a Person, and especially a Person who does not simply say "do X in Y situation," we can come across some conflicting views.
It is the goal of the Church in every generation to help the people of God to know Christ given the unique circumstances of each generation, without veering off into craziness that jeopardizes their love of God and neighbor. Ultimately it is up to the individual priest or bishop to exercise the right balance between akriveia (precision) and economia (house building) in each particular situation. For the priest it is more about the daily lives of parishioners, and for bishops about the actual teaching of the Church.
Anyways, this is starting to turn into an essay, and for that I apologize. But it is necessary to understand the details of the things we are talking about if we are to really talk about them. I do not say this to offend you, but out of recognition that many here are probably unacquainted with or have sadly had bad experiences with religion. To the degree that I can use my background in religious studies and my experience across various religions to help explain things, I am trying to do so.
My comment wasn't meant as criticism; I think we are talking about different issues. You seem to be addressing the acutal theology of this issue; I'm talking about how people can and do interpret the same scripture in many ways.
For Jews that believed in an afterlife, many did not expect something that we would consider to be like Heaven or Hell. Rather, Hades was the destination of all those who died. Hades was, for lack of better words, a place of gloom, essentially a jail of all the dead. For those who lived good lives according to the Law, the best they could hope for was that they would find themselves in "the bosom of Abraham": close to the religious they loved, but certainly not something like Heaven.
St. John the Baptist is also known as the Forerunner, the person who helped prepare the people for Jesus' message. He was the forerunner not only in life but also in death: he preached in Hades of the Messiah who, far from being a worldly conqueror, would truly liberate all humanity: He would liberate them from death and Hades.
To cut a long story short, the Resurrection is the death knell of Hades. The jail which kept the dead prisoner was destroyed in taking upon the Sinless One, God Himself. And those who were liberated were those who received the message of St. John.
It is of course not possible to know what form St. John's message took. It must have been something that even the dead could perform, though. And the dead, lacking life, do not really have anything to give. So I will -- perhaps unwisely -- hazard a guess that it might have taken this form: love and forgive your enemies.