There was no concerted effort during the early medieval age to destroy information, as there was no central authority with enough clout to enact such a thing.
That is a false statement. They weren't out to destroy all information, just the unapproved kind. The Holy Roman Empire was a central authority that started the book burning. Don't even get started on the forced conversions they perpetrated.
Recall the 'Dunces' were a well respected 'dark age' catholic intellectual community. They believed all knowledge was already collected in the bible and the works of Socrates and Plato.
Their traditional head gear was used to mark the morons in class, of course that's no longer acceptable.