Australias purpose in Iraq

On Sunday I cut out an article, which I only got around to reading today.
It was titled "Haunted by fear of Iraqi ambush". It was basically of a Corporal who served in Iraq for seven months and his thoughts on western; or at least Australia's occupation in Iraq. He has thoughts that run along the line of, "Why are we there? Why did I go there? " and "I don't think we should be in Iraq. I sit there and look at it and think it's all civil war now and we're just getting in the way."

I myself don't understand why Australia is still in Iraq. So I search up wikipedia. (good ol' wiki. Like an uncle that knows about everything and won't hesitate to share the information. )
Here goes:
Starting off, was the Invasion of Iraq led by the Bush Government with an objective of disarming Iraq of weapons of mass destruction, to end Saddam Hussein's support for terrorism, and to free the Iraqi people. After Saddam was overthrown, an attempt was made to establish new gov. regime's which failed, leaving Iraq in a state of turmoil , many countries withdrew their troops.
2003 - Saddam captured
2004 - Iraqi Insurgency
2005 - Election for Iraqi government, U.S announcement of withdrawing troops is canceled as suicide bombers tore through the country.
2006 - civil war ensues, Saddam is executed.

Well.... that didn't give me an answer, instead has filled me with more questions.
Why didn't Australia withdraw when the other countries did?
If America had not interfered, even though it would mean Saddam was still ruling Iraq, would it have been better for the country?
I mean from what I know, i don't think weapons of mass destruction was ever found. With the plan to attempt to 'free' the Iraqi's, instead has backfired and have thrown the people into a living hell.

Hmm...
You know what i think?
Damn those who make it their business to stick their noses into everyones else's business.