No problem, I do not expect immediate response. Now, let me jump right in.
It is no more reasonable to say that you "only" need to know about "life and the universe" than for me to say that I believe in God. That's a lot of "only" left on your part. ;)
Christianity is like the fact that you have grown up with something so ordinary that you consider it completely normal that a human does not simply end the life of another human without bringing moral principles to their conscience. There was a time before Christianity when this was the case. If the cults before the times of Christendom was to perform bloody human sacrifices, then it was a coherent one for the people of that time. This coherence crumbeled under the influence of the beginning of Christianity (and else monotheistic movements).
Following the New Testament, Christians believe that the self-sacrifice of the Son of God has made all human and animal sacrifices to God superfluous. Since Anselm of Canterbury's doctrine of atonement, Christian theology has attempted to bring the diversity of the New Testament into a common system. In modern theology, however, ideas of an atonement that God needs to satisfy his wrath are usually rejected.
The reformed theologian Karl Barth replaced the concept of atonement with the concept of reconciliation. Jesus' substitutionary assumption of guilt is interpreted as the deepest justification of human rights and the beginning of the end-time liberation from the void (Barth's term for sin). All-reconciliation is considered as a possibility.
https://de.wikipedia.org/wiki/Menschenopfer
In any case, I think that this transition from ritual human sacrifices to more moderate symbolic acts was a merit of the Christians. For me, the Ten Commandments (the most important doctrine, I would say) resulting from Christianity stand as the best ideal to date. This ideal is an expression of faith in God, not an expression of a belief in the infallibility of human beings, because that is what Christians recognise: that "every human being is fallible". As normal as this statement may sound, it cannot be assumed as an official doctrine by former cultures. Once a doctrine becomes normal, it's often very hard to see, which is quite a paradox.
Now, if you say that Christians themselves behaved cruel and violent, this would be true. It nevertheless makes the ideal not to be cruel and brutal not obsolete, though. It underpins it.
The ordinary (I shall neither kill you, nor cheat on wives and husbands, nor take away what is yours) comes out of the extraordinary, not the other way around.
But if you would think that violence, brutality and oppression is the result of having faith in God then you'd argue that such faith is not needed (and you may lump the Christian monotheism together with the cults of multi-theism and other ancient cults, while they differ vastly from one another).
Like Chesterton said: "The Christian ideal has not been tried and found wanting. It has been found difficult; and left untried." Here is the bit of context out of his writing:
.. it is actually true that the Reformation began to tear Europe apart before the Catholic Church had had time to pull it together. The Prussians, for instance, were not converted to Christianity at all until quite close to the Reformation. The poor creatures hardly had time to become Catholics before they were told to become Protestants.
This explains a great deal of their subsequent conduct. But I have only taken this as the first and most evident case of the general truth: that the great ideals of the past failed not by being outlived (which must mean over– lived), but by not being lived enough. Mankind has not passed through the Middle Ages. Rather mankind has retreated from the Middle Ages in reaction and rout. The Christian ideal has not been tried and found wanting. It has been found difficult; and left untried.
I'll come back to what we seemed to agree on at the beginning. That the interpretation of what the religious scriptures have left us allows for intimate contemplation and interpretation. This does not mean that each interpretation is equally good or equally bad, but that one is better than the other. If all were equally good/bad and there were not a few that were better than the many, I could just as well say "Everything is up" - I wouldn't have said anything at all.
"I swear by God to be faithful to you" sounds completely different from saying: "I promise that I will not break my commitment." (but then, you could ask how many times you even say that nowadays to someone, and mean it).
"I bind myself to you in the holy sacrament of marriage until death do us part" has a completely different meaning and power than not doing and not thinking such things. If I neither think nor do such things, then I have not only lost sight of the ideal, but simply allow the less ideal to happen. Why do you think that films like Lord of the Rings or Game of Thrones move us if those involved in the story didn't really believe in the oath they had taken? Aren't the traitors in these stories precisely those cynics and godless people who believe in nothing?
You said:
We could not play the same game with lightning from the sky, but since we base so much of our existence and beliefs about the world on cause and effect, we could not help but imagine a cause for what we saw. That's all God is, in my opinion.
Saying "that's all there is to it" in relation to God is like saying to me as a Christian that my faith is "nothing but" a spiritual (even helpless) explanation in the absence of any intellect on my part in this regard. Or saying to a child who wonders about its existence: "Oh that? That's nothing. You just came out of your mother's womb. And that's all it is." While it factually is true,I find it not true in the whole sense.
Because I believe in God doesn't mean I've stopped wondering, in fact quite the opposite. Whereas at another time in my life I agreed with you and even felt superior when I said to my friend: "Oh, Christians are only Christians because they can't stand the fact that instead of a miraculous explanation, God, there is a very simple one, and anyway. We live and then we die. That's just the way it is." But even back then, while I said it, I already felt there was a sort of fatalism and disappointment in myself. I tended to be a materialist but then, I never fully became one.
I greet you and thank you for the so far debate.
RE: The BIBLE and the BIG BANG.