The book that was being reported upon is written by an American, Tom Nichols, who is a professor at the U.S. Naval War College, and a conservative. You would be better off questioning why an American says this than why a Canadian journalists reports on what Nichols is saying. It may be that the US is ceasing to be a great and enlightened country that both Americans and Canadians worry about. Instead of making America "great" again, you may be more concerned about making America wise again.