Hi Meikleour,
Surely the GRD SPLS are not activated by the Flight control check?
Agreed.
But suppose you forgot to stow the ground spoilers after landing, and shut the engines down. The spoilers would gradually stow themselves with the loss of Hyd Pressure, so there is a chance you'd miss the clue on the walk around. After the next engines start and taxi out, if the spoiler handle was still in the armed position - then Airbus think there is a chance of Max Auto Brake being applied when the MAX switch is selected.
If you do the flight control checks first, then you should notice the ground spoilers are up, stow the handle, then arm it.