Did you read the article?

Hottot said Kazazi was well aware of those requirements and planned to file his disclosure form during his four-hour layover in Newark. The form instructs travelers to file the paperwork “at the time of departure from the United States with the Customs officer in charge at any Customs port of entry or departure.”

Addressed in the article. You're supposed to declare to customs when you leave the country. He would have been leaving from Newark after a four-hour layover.

Also in the article: CBP had 90 days to respond after Kazazi decided to take the matter to federal court, but over a month after their deadline passed are still holding the money, and are refusing to comment.

The money was seized at departure of the domestic leg of this trip, before he had an opportunity to report it at the port of departure for his international leg.

https://www.fincen.gov/sites/default/files/shared/fin105_cmi...

(1) He wasn't trying to hide it.

(2) It was a domestic flight; he says he was going to declare it when boarding the international flight.

This was all in the article.

At this rate the various LEAs are going to make muggers, bankers and other professional thieves jealous.