I may well be overthinking - people have often told me I have a tendency to intellectualize.
However, I'm not saying anything original or shocking - this is standard first-year-at-college theology. There's a whole sub-area of theology called 'soteriology' which studies the death of Christ and how it relates or doesn't to the salvation of humanity.
I think we have different terms of reference here, truethat. You make assertions like 'it is what God said. It is plain as day' or 'It isn't a matter of interpretation on the actual reality', which imply to me that you believe that we can know God and his plans directly, even while you seem to have a strong aversion to them. I put to you that this isn't the case.
OK, here's how I see it.
Actual reality: Jewish priests sacrificed lambs in the Temple at Passover.
Interpretation of why this happened: Either 1. God exists and has weird ideas about murdering lambs (literalist view), or 2. the Scriptures which mandate this give an account of how early Israelites understood their relationship with God, in light of the common religious practice at the time of sacrifice for propritiation, or, 3. of course, God doesn't exist and they made it up.
Now, of those options, I choose Option 2, as do many (most, historically speaking?) Christians. You, however, seem to be advocating Option 1.
A similar thing applies with Jesus's death. I think that theories which say Jesus was a blood sacrifice are religious rationalisations or explanations of the actual fact of his death.
Your example of the Eucharist seems to make this even clearer. There are a lot of debates about the status of religious language. The various theories of the Eucharist (transsubstantiation, consubstantiation, Real Presence, symbolism) and so on, all seem to be theological interpretations of Christ's original institution of the Last Supper, as described in the Gospels. Whether you're a Catholic, Lutheran, Baptist, whatever, when the president at the Eucharist says 'this is my body' s/he is not making a simple statement of fact as if s/he was describing what s/he had for breakfast. Even the Catholics talk of the mystery of the Eucharist.
Of course, many fundamentalists and literalists have mistaken the map for the territory and speak as though various theories and bits of religious language - Christ's death as blood sacrifice, or transsubstantiation at the Eucharist - were propositional statements rather than interpretations of a bigger mystery. However, I would argue that they do not represent the whole of Christianity, by any means. And that I am being entirely orthodox in saying so.