Thanks to wikileaks we now really know–or at the very least have a strong suspicion of–why the satellite US 193 was shot down.
Wikileaks highlights one item in their summary of the leaked powerpoint presentation:
Of particular note in the document, is the fact that along with FEMA and safety task forces, a Department of Defense “Payload Recovery Task Force” is expected to respond to the impact site approximately 3 to 6 hours after the impact. This suggests that there may be some validity to rumors that US-193 is being intercepted on national security grounds.
My comment would be that if the “payload recovery task force” will respond within 3 to 6 hours, that means it has been organized and is ready to scramble to the site of the downing. Of course, what are they concerned about? Two possibilities: some fancy imaging technology (ground penetrating radar at the top of that list), or perhaps the cryptography module, which would reveal how the satellite communicated with the ground. If that information were acquired, it is just barely conceivable that someone could acquire control over one of the other spy satellites, or eavesdrop on the communications.