[Legbreaker]

Something else to think about is that you don't necessarily need to attack the satellite itself to render it useless. If it could be "persuaded" (by hacking) to fire it's thrusters and destabilise it's orbit it may just destroy itself (could use up all it's fuel before it's true owners regain control).
Also attacking and destroying ground stations could have the same result - updates and orbit corrections would be near impossible to upload to the satellite and end up with the same result as direct hacking (re-entry).
Physical destruction of ground stations isn't all that necessary either - as previously mentioned EMP will wreak havoc on computer systems and in the time it takes to conduct repairs...

All in all satellites are pretty damn vulnerable in a world wide war involving nukes. In a conventional war then yes, you'd probably need to go after the satellites themselves as the level of destruction on the ground just isn't going to be a major problem - control can be handed off to another ground station whereas EMP is likely to render ALL ground stations out of action at least temporarily. Conventional warfare just isn't going to cut it to eliminate more than a small percentage of satellites.