there's a difference in semantics between clinical reason and billing, agreed, though it seems that the news article did not sensationalize the study, and the study uses at least one valid code that can be a primary reason for a visit, and while I'm absolutely just a random dog on the internet, for me the overlap in meaning seems significant to warrant the use of this term.

https://icdlist.com/icd-10/F63.0

https://icdlist.com/icd-10/Z72.6 "The code is not accepted as a principal diagnosis "