The Iraq war was sold to the public based on lies and Charles Krauthammer was one of those key promoters pushing those lies. For a good segment of the population at the time it was very obvious this was being done.
Opposing the war of aggression waged immorally, illegally (under international law and arguably— given the bad faith in the application of the conditional authorization by Congress—under US law as well), and incompetently by the Bush Administration isn't the same thing as defending Saddam Hussein (who is no more the Middle East version of Hitler than many other past or current leaders in the Middle East, many of whom—including Saddam, at the peak of his most Hitler-like actions—have or had the direct backing of the U.S. government, including—again, also specifically in the case of Saddam Hussein—the particular individuals most responsible for military and defense policy in the Bush 43 Administration. )