If you look into what Saddam was doing to his own people: It had to change.
It may sound extremely cynical but … Saddam was the only person who knew how to maintain order in Iraq without extreme bloodshed.
Saddam’ regime was successful at managing the country at the cost of 15-20 thousand civilian deaths per year. Since we got there, an estimated 600 thousand people have died, either killed by Americans or their fellow Iraqis. No guarantee that the situation will stabilize if we withdraw.
Some countries just don’t seem to be ready for democracy.