The 17,300mph is the centripetal velocity (I doubt that any weapons satellite would be in geostationary orbit; they'd be in low, small, quick orbits like the spy satellites).
Here's an example of why you don't add that on:
When you drop a ball from (say) 2m, does it move forward?
No.
That's because it's attracted to a central point, and all rest frames are valid (remember, from the perspective of the surface of the earth, a geostationary orbit is, well, stationary).