From the FCTM.
The thrust levers must be confirmed at ”idle” before engine-start. If the thrust levers are
not at ”idle”, the thrust increases above idle after engine-start, and can result in a
hazardous situation.
However, an ENG START FAULT ECAM warning triggers, to indicate that the flight
crew must set the thrust levers to ”idle”.
I admit I have never tried it before, why should I have! But ok, assuming you are right and the engine won't start...what on earth is Airbus talking about then?