Japan is not Iraq.
Iraqis are not Japanese. For one thing, Japan is culturally unified. One can't even begin to say that about Iraq.
The Iraqi emperor did not go on the radio, disavow his godhead, and direct his people to cooperate.
The transfer of authority to the American occupation forces was clean and complete in 1945. In 2005, not so much.
The analogy doesn't work because the groups and conditions are too different.