Very good question, sir!
Unfortunatly the answer is hidden. This may sound hateful and mean, but if you put all of their rhetoric together the picture becomes clear. This may take a liitle time.

They do not believe that the U.S. or it's citizens deserve what they have, freedom-wise or materially.
Since they believe it is impossible to bring the rest of the world to the status of the America, they will settle for some kind of middleground between what we have now, but not quite the 3rd world. Basically they have no faith in mankind to do good. And since also believe they are "the good guys" they will be at the top of the food chain and won't have to worry about the things the citizens / subjects will have to worry about(food, water, housing, fuel).
Liberals know the money from taxes may have come from us, but to them it is the price we are to pay in retribution for what we have.
They know that when we are armed we are able to tell them "no". This is something that no other peoples in the world can do. They resent this, because they believe they know what is best for us, even if we don't understand why. While I seriously doubt that it will ever come to this, in my lifetime at least, if it does I know I will fulfill my duties as a citizen.
Disarming Iraq pulls them away from their domestic issues. Issues they beleive they have the ways to fix, but unfortunatly these ideas will only make them worse, cause bigger problems or have no effect. Crime=disarm the citizens, Health Care Crisis=Taxpayer Funded Health Insurance, Unemployment=extend benefits, Pollution=ban SUV's, buget deficit=raise taxes, etc. etc.
My parents put me out of the home nest when I was done with high school. At the time I resented them for it, but I now thank them. Because I discovered that if I didn't get my shit in gear, I'd wouldn't make it down the road. I never want to live under anyone's wing ever again. Especially these dirtybirds. Cause I'm always going to get shit on.