So, the first rule of examining an article like this is to know the source. And the New York Post is not bad, actually. They lean right, but not too hard, and generally provide solid news. They have had some issues with accuracy, such as reporting that 12 people died in the Boston Marathon bombing, and publishing a picture of 2 individuals accusing them of being the bombers when, in fact, they weren't.
This particular writer, however, has an obvious axe to grind. Look at his history at the Post.
You keep bringing up "anonymous sources." Do you realize that there's a difference between one guy saying something, vs at least 4 people independantly confirming it? Because there were 4 different people who confirmed the Atlantic story about the visit to Aisne-Marne cemetery. vs... well, in the story you posted, there is a single person, with no confirmation from other sources.
Let me repeat that. THERE WAS NO CONFIRMATION FROM OTHER SOURCES. That's the first rule of journalism. You learn it reading Spider-Man comics. I mean, this is some serious Jacob Wohl stuff, here.