They really want history as it actually was to go away

“In general, ASNC teaching seeks to dismantle the basis of myths of nationalism - that there ever was a ‘British’, ‘English’, ‘Scottish’, ‘Welsh’ or ‘Irish’ people with a coherent and ancient ethnic identity - by showing students just how constructed and contingent these identities are and always have been.”
Because people believing in anything but the EU screws with their plans.  Having a bunch of peasants who actually believe in their country as something special is Bad.