Just think of it this way: The handle controls the speed brakes and pulling it up arms the ground spoilers. Or to say it this way: It's the speed brake lever, but it also arms the groundspoilers. That's the basic idea. No it gets a bit more complicated, though, because you don't get speedbrakes with Flaps Full, on the 320 only about 1/2 of max deflection with the autopilot on, after touchdown with one wheel, there is only partial deflection until the other one is down and even if you don't arm the groundspoilers (again: by pulling the speedbrake lever up) you still get groundspoilers when one thrust lever is idle and the other at least idle reserve ......