From Dennis Preager at National Review Online, Learning the Wrong Lessons from Nazism:

The first lesson was that the Right is evil, not merely wrong. Because Nazism has been successfully labelled right wing, virtually every right-wing position and leader has been either cynically or sincerely characterized by the Left as a danger to civilization. That is why the Right is so often labelled fascist and compared to Nazis. Vast numbers of people in the West truly believe that if the Right prevails, fascism will follow.

Of course, Nazism was not right-wing — certainly not in American terms. How could it be? Right-wing means less government, not more. Nor was it left-wing, even though “Nazism” was an abbreviation for National Socialism.

Nazism was sui generis. It was radical racism combined with totalitarianism; and racism as a doctrine is neither Right nor Left.

We have no contemporary movement of any major significance that is Nazi-like. The closest thing we have is Islamist hatred of non-Muslims — but even that is mostly religious rather than race based.

The association of Nazism with the “right wing” is one reason many Jews loathe the Right. In the Jewish psyche, to fight the Right is to fight incipient Nazism.

Fifth and finally, the Left has affirmed pacifism as an ideal. One would think that the most obvious moral and rational lesson to be learned from the Nazi experience is the need to fight evil. After all, if decent nations had not been as militarily strong as they were, and had not been as willing as they were to use that might, the Nazis would not have been defeated, and many millions more “non-Aryans” would have been enslaved and murdered. But the Left, including, sad to say, Germany, did not draw that lesson. Instead of learning to fight evil, the Left has learned that fighting is evil — and it has taught this to two generations of Americans.

It is easier to demonize oppostion than to justify your position and few pejoratives are as effective as as branding one a nazi.  Hayek’s  Road to Serfdom clearly argued that statist control is the danger and that is the position of the modern American Progressive.