I personally do not agree that killing Al-Awliki violates American principles. The bastard deserved what he got and we were perfectly entitled to give it to him.

But I DO agree that there are too many who are too quick to criticize those who hold opinions contrary to theirs as being un-American, or un-patriotic. As you point out, by a process I call "Adjectival linguistic creep", other political, social or economic opinions have been added to the list of crimes those with unpopular opinions have been accused of committing. For example, we have to defend ourselves of charges of being "Socialist" or "Statist", even though we may not be one, or even agree with the definition being bandied about by the accuser. Not to mention, being a socialist or statist is not illegal, or even immoral.

In a way, this behavior has turned out to be quite useful. Now that being a bigot is no longer socially accepted, this is a convenient way to locate them. And now that there is confusion as to just what a fascist is, this is the perfect to way identify them.