Why can’t we compare US policy to the Third Reich?

“The relevance of Third Reich Germany to today’s America is not that Bush equals Hitler or that the United States government is a death machine. It’s that it provides a rather spectacular example of the insidious process by which decent people come to regard the unthinkable as not only thinkable but doable, justifiable. Of the way freethinkers and speakers become compliant and self-censoring. Of the mechanism by which moral or humanistic categories are converted into bureaucratic ones. And finally, of the willingness with which we hand control over to the state and convince ourselves that we are the masters of our destiny.”