there is no further classification in your "faq" than:
"(C) Misrepresentation.-
(i) In general.-Any alien who, by fraud or willfully misrepresenting a material fact, seeks to procure (or has sought to procure or has procured) a visa, other documentation, or admission into the United States or other benefit provided under this Act is inadmissible."
That is what the letter says, according to the news article cited in the OP. It is also what the applicant explicitly denies, describing in detail what exactly happened.
"Weber told The Associated Press, whose bureau chief in Buenos Aires is a member of the foreign correspondent's association, that she still doesn't know what she allegedly misrepresented, and suspects U.S. officials don't like what she's researching."
"Press freedom groups including the U.S. Society for Professional Journalists and Reporters Without Borders have challenged what they call selective enforcement of the visa requirement. The Organization for Security and Co-operation in Europe has accused the U.S. of violating its treaty commitments to ensuring freedom of movement for journalists."
http://www.forbes.com/feeds/ap/2011/04/12/general-lt-ar... Perhaps your State Department ought to come clean about what they are up to.