That's not quite true.
A defender *CAN* get a call in their favor. Not every time Nate McMillan strips the ball from Michael Jordan is a foul (conjuring up one image *CERTAIN* to upset Skander (and me, for that matter)). And just because it's Kobe Bryant elbowing Mike Bibby in the head doesn't make it a no-call. Or at least that's the hope.