'Can someone explain this to me? As I think he's talking shite.'
It's the airflow he's really talking about. As air is accelerated over various parts of the airframe, the upper surface of the wings, probably the canopy, the localised airflow reaches Mach 1 before the aircraft as a whole does. Hence the Transonic region which is something like M0.8 to M1.X*, why above M1.0, well the air is also slowed over some regions of the airframe so is still going subsonic when the aircraft isn't.
Early supersonic aircraft had more problems in the transonic region than the either side of it, although these days with area ruling it's less of a problem. With the F-35 I'd imagine the flight control system masks any issues from the pilot.
*Where I can't remember what X is typically.