I don't disagree with you, but aren't the militias backed by the public and doing the deeds that the people would like to see done?
How much percentage of the population belong to the militias?
The average Iraqi hates the militias and would like security resorted by a national Army and police force. However, they also fear that if there local militia just went away that they would just end up being butchered by a rival militias. That is why the government needs to be evenhanded going after them.
All the militias combined (not counting the Peshmerga) as well as the insurgency are probably no more then 100,000 men.