The reason that 'D-Day' (Normandy invasion) was called a liberation was that the invading forces were willing to take on an entrenched enemy and were willing to suffer fairly massive losses in doing so, and the immediate improvement in conditions following it.

The reason why the rest of the world refuses to accept the situation in Iraq as a liberation and in stead perceives it as a cynical battle for control over resources is that:

  1) the invaders are not prepared to suffer losses on par
     with their 'enemies'

  2) more people have died under the 'liberators' than 
     would have died in many years of previous occupation

  3) the situation in Iraq is still viewed through the 
     terms of lives lost by the invaders instead of lives
     lost by those 'liberated'

  4) there would not be as much or more accent on 
     protecting Iraqs oil resources as there has been 
     on saving Iraqi lives

Whether or not people get killed by 'insurgents' (one mans insurgent is another mans freedom fighter), 'enemy combatants', 'friendlies' or whether they're collateral damage, it doesn't change anything in the fact that those deaths could have for the most part be avoided if the invaders were willing to take the losses themselves.

If you liberate someone you place yourself in a position of sacrifice, you're willing to go the distance in order to protect those you liberate. A hostage rescue team goes in knowing full well they're going to try to protect the lives of the hostages at all cost. A hostage team that would go in to protect their own lives at significant extra risk to the lives of the hostages would not get much recognition, even if they would save the occasional hostage.