You're focussing on the wrong part of that sentence. Here's the part that applies: "If a player goes to the ground in the act of catching a pass (with or without contact by an opponent), he must maintain control of the ball until after his initial contact with the ground, whether in the field of play or the end zone."
The ball obviously touched the ground, and then moved/he lost control momentarily.
Now, all that being said, my nuanced response based on watching that play numerous times is this:
1. Cotchery is going to the ground during the catch, which brings these ground/control issues into play.
2. The ball obviously contacts the ground.
3. Immediately after contacting the ground the ball moves, and appears momentarily out of Cotchery's control.
So, the call not to overturn the original incomplete is defensible, and most likely correct.
However:
4. I think, from watching this a zillion times, the ball moves not because it contacts the ground, but because Stewart's helmet hits Cotchery's hand and keeps his hand from rolling with the rest of his body. So, I believe the ball doesn't move due to contact with the ground, but due to Stewart's contact with Cotchery's hand. And after that Cotchery gains control again, and the ball never touched the ground again.
So, in conclusion, this might have been a catch. I think that if it had been ruled a catch initially, that it likely would not have been overturned either.
The determining question, imo, is whether the ground caused it to move, or Stewart's helmet. Since those two things happen virtually simultaneously, it might actually be a combination of the two (which would make it incomplete).
This is a play that there really is no clear-cut "correct" call. Based on the rules as written, a good faith argument can be made either way, and the conclusion depends on how much weight the observer puts on what caused the ball to move, either the ground or Stewart's helmet.