There is no oversimplifying happening here. There is no documented procedure to switch to direct law in an Airbus.
In fact, the only way to get into direct law on a fully functional plane is to start pulling circuit breakers for the (redundant) flight computers and inertial reference units.
In fact, the only way to get into direct law on a fully functional plane is to start pulling circuit breakers for the (redundant) flight computers and inertial reference units.