One way of remembering the mode logic is to understanding what the elevators are controlling. In GS the task is to maintain the flight path (path on elevator - speed controlled by the AT); after a speed reversion the elevator adjusts pitch attitude to maintain speed according to the thrust level (speed on elevator – power rating).
From GS mode a speed reversion without power change could be hazardous, and if power is correctly selected the end result is similar to TOGA … so from GS why not go to TOGA. This is the design logic.
I also suspect that where Airbus uses alpha as the switching parameter (maintains an alpha floor), speed reversion still uses airspeed as the dominant input even if alpha is introduced somewhere … hence the mistaken terminology – blame the salesmen.
A possible confusion is that pilots think of speed reversion as speed protection. The Airbus concept can be considered as a full protection system (but not totally), whereas speed reversion only applies to some modes – the difference between semi automatic (occasionally/mode dependent) and ‘fully’ automatic. These differences are aspects of critical safety knowledge when operating highly automated aircraft and the issue also applies to systems other than AP/AT.