The reason the discourse of exceptionality is powerful is that it reinforces the general mindset of literary humanists, the taste for everything counter-hegemonic. Even if exceptionalist discourse is hegemonic within academia, it must be seen as alternative.
I shouldn't be misconstrued here as advocating against the alternative and counter-hegemonic. After all, I am one of the tribe.
González Echevarría starts Celestina's Brood by saying it (La Celestina) is the most suppressed classic in the Spanish canon. That automatically gives him some "points." If it is suppressed, then it must be dangerous and radical. Furthermore, the critic who makes this argument benefits from the mystique or romance of un-supression, uncovering the repressed, and being dangerous and radical himself. (Right now I'm at the stage of figuring out how these arguments work, not with deciding whether I agree with any particular one.)
Later on, he says that Spanish-language writers like Rojas are radical, but that the theorists are not. Spain has no Bataille... I could also collect all the quotations where Spain doesn't have something (enlightenment, modernity, progress, theory). The collection of quotes would basically give me the answers I need. My MLA talk is already too long! Help!