I think the main character is a Savant, who others view as an idiot. The title and its characterization are ironic. He is the smartest character in the book, but viewed as an idiot, due to a consistently ignorant society.

Not unlike, for example, Sufi poets who claim to be gods and then are humiliated and executed for heresy. His label of “idiot” is his execution. A crowd crying to crucify Christ.