Judging the Iranian middle class: instant journalism and analysis

While I have been critical of some of the writings of Robert Worth, I do believe that he is a serious journalist.  But I was thinking this morning when I opened my New York Times.  He has a long article judging in it that the Iranian middle class is on edge.  I am not arguing for the sake of argument, but this is a tendency in Western press.  How they can send a reporter to a foreign land (and the reporter most often than not does not know the language) and they expect him/her to write a piece about the public mood and preferences of millions of people--all based on a few days trip to the country.  I mean, Worth stayed for days in Iran and he is able to judge the entire mood of the entire middle class of Iran?  I mean, really.  I have lived in the US and I know English but would I be able to write an article--without resort to public opinion surveys--about the mood of the American middle class?