The internet is indeed a funny place with this story.
If I parse it together right, a Youtuber who unboxes Magic cards gets sent a box he would have every single idea is the wrong set, a set not even released yet. Wizards, fresh off their PR issues, hires a notorious (but recognized) investigative outfit to connect with the Youtuber and get their property back after trying and failing to get in contact with him.
I really feel with a lot of this, if you Mad Libs this, and change out names, the response is different. If, instead of what's going on, Paizo accidentally Fedex's playtest documents for their complete but unreleased adventure path to a Youtuber who likes to break TTRPG news, and Paizo hires the Pinkertons as legal, bonded third-party contractors -- no one bats an eye.
Clearly there must have been time between when he recieved cards that, due to his profession, he absolutely knew weren't released and when the Pinkertons showed up. The agents didn't show up the next day. This was someone I'm betting was hoping to beat people to the punch and do an unboxing at the soonest chance he thought he could do.
And it's not like they're just confiscating their stuff back - clearly, and rightfully, he's being compensated for it.