Because the majority of those countless other regimes don't pose the same level of threat Iraq posed. And, you pick your battles one at a time and the situation dictates how to handle different threats. North Korea- different situation, different threat, different means to handle it (funny how the Russians and the Chinese are all for having the U.S. beat up Kim Jong II). The pretense for the war was never liberation and it isn't now. It was always WMD and not large stores of readily deployable ones either. It was to prevent any quantity of chemical weapon being distributed to a terrorist organization. Do you remember some event that happened, oh say around, September 11th? Terrorists dont need an army or a large store of readily deployable WMDs to do the kind of damage the war was meant to help prevent. Big effin deal they had a couple centrifuges? It is a big deal because 1. They are illegal according to Iraq's commitment to the NPT 2. They cost millions of dollars to acquire and can take over 10 years to develop (if you miss the point here it means the are millions of dollars and ten years closer to the goal of developing a nuke) 3. It is in violation of the original Gulf War Treaty and UN imposed sanctions (that your buddies France, Germany, China, and Russia seem to have forgot they agreed to help enforce). The scientist who revealed these items basically said there is plenty more where that came from (buried in the Iraqi dirt) and other Iraqis in the know are still currently to scared to speak out. There is anti Russia, China, and Germany backlash but France is the one who said they would veto the final resolution the US put forth- w/o even reviewing it (they vetoed one before it before the Iraqi's did). France was belligerent and infantile in the Iraqi war debate. Thats why they received the majority of the backlash. There was plenty of opposition to Chirac and Schröder in their respective countries but the liberal rags in the U.S. chose not to print a view different to what they believe.
The U.S. and our government are far from perfect and our history has its share of black marks. But, it is leaps and bounds ahead of any other country or government that exists today or has ever existed when it comes to improving world relations. Its people like you who choose to condemn and ridicule instead contribute that slow us down. You continue to be ashamed of yourself and the country and government that give you a higher standard of living, more freedom, and is more honestly focused on achieving positive world wide relationships with other countries than any other country or government in the history of the world. Dont speak for me. Now, I need to get on my BMW and ride over to Sams, pick up a good bottle of Bordeaux, and come home and order in some Chow Mein.