I thought they finally found Satoshi Nakamoto (the title is so clickbait to me), well after reading the article he just explained how they the NSA identified Satoshi. So the point is using "Stylometry" but in my opinion it will be hard if Satoshi is more than one person. I belive Satoshi is a smart person who really thought through many things in order to hide his identity including this "writing style".
Sounds interesting but still its hard to believe, and why would this agency will take so much effort just to identify satoshi his not even a criminal still this is another theory and not proven yet.
According to the article they think that Satoshi was an agent of Rusia or China and would be a threat to them in the future.