If you are asking "what did Arnett do that Jennings has not", I would reply that Peter Jennings more than deserves the boot, but even he has not openly stated that his purpose is to undermine our efforts.
Our reports about civilian casualties here, about the resistance of the Iraqi forces, are going back to the United States. It helps those who oppose the war when you challenge the policy to develop their arguments.Throw on top of it his history of subversive propaganda (the Baby Milk factory spin, the Sarin gas lie, etc) and it is clear that Arnett is a fifth column bastard who should be instant market-death to any western media outlet that hires him.
That is a true statement. How does repeating the truth amount to a reason to be fired ? Jennings on the other hand makes up lies in the form of questions.