You noticed that "things hidden since the creation of the world" is a quote from the Gospel, right? (Matthew, chapter 13, verse 35.) And that Girard's point is to show that the Gospel tries its best to uncover the scapegoating phenomenon?
If you use this quote to title your book, how are you not identifying with the "prophet"?
Matthew 13 ends with this: "Coming to his hometown, he began teaching the people in their synagogue, and they were amazed. [...] Where then did this man get all these things? [they asked] And they took offense at him. But Jesus said to them, “A prophet is not without honor except in his own town and in his own home.”
It seems pretty obvious to me, by using this quote taken from this context, that Girard is referencing himself and seeing himself as Jesus, regretting that he's a prophet but in his own country...
I have not read the book, so maybe you have an impression based on the contents that justifies this, but standing on its own this statement is entirely ridiculous. How are you identifying with someone just by using a quote as the title of your book?
Alas, it continues to be ridiculous after one has read the book too.
As a layman, I try to sum it up from my memories: according to Girard, desire does not stand by itself. It only rises to meet another's desired object. Somehow: you don't desire a shiny car because of the shine of the car by itself, but only because someone already has or desires a shiny car.
This phenomenon generates conflicts when the desired object can't be shared. This leads to crises in human groups where the only escape was traditionally to take someone (anyone, actually) as culprit for this crisis and kill them, honestly pretending that they are responsible the the group disease.
I don't recall how, but Girard says that this killing cures the group. Which proves to the killers that 1) the scapegoat was indeed responsible for the trouble and 2) it was in the situation of providing the miraculous cure and is therefore some sort of goddess.
This is what Girard explains but refutes to have found by himself. According to him, denouncing this unconscious process is the very purpose of the gospel. This is what has been hidden since the creation of the world.