I don't think she is as anti-President Bush as you think. After all, note that Rowling depicts the newspapers in the wizarding world somewhat poorly; remember Rita Skeeter Goblet of Fire (what a tattletale and then some!), Luna Lovegood from Order of the Phoenix (note how Luna is quite a bit embarassed by her father's scandal sheet newspaper at times), and how everyone more or less puts down The Daily Prophet in the latest novel.
Good points. I also found how Harry was villianized in the Daily Prophet in the 5th book to be a parallel of how Bush is villianized in our media. May not have been her intention, but it was a striken similarity.