As I see it,
You should look !
Watch a 757 the next time one touches down. The spoilers will deploy before the nosewheel has compressed, or indeed touched the ground. As haughtney1 has suggested, read it again.
I appreciate you and /or kestrel may think otherwise, but I would be concerned if Boeing feel otherwise because every time I have landed one for the last 20 years the spoilers have activated with the main gear untilt sensors prior to nose wheel touchdown ( other than when the speedbrakes are disarmed of course ). The point about the reversers was simply to add that they are also able to activate the spoilers even when the speedbrake lever is disarmed.
The reference you have provided, refers to the components of the Air /Ground sensing system. You will understand that not all constituents of it are relevant to each and every system.
If you disagree perhaps you could explain this seeming anomaly ?