You can read the full statement in the link above, but this reads as a desire to cut down on the financial strain of legal work. As an extra wrinkle, Paizo says: “We offered a marketing agreement to [Archives of Nethys to] make the change less impactful, but those conversations were not concluded before they chose to publish their notice.”
Original story: Pathfinder 2e’s developer, Paizo, gets a lot of slack from me—because all told, Paizo is incredibly generous. As a system, PF2e costs basically nothing to play. Every rule, additional class, extra monster, etcetera is available online for free, either through platforms like Demiplane or via its very good Foundry integration.
The only thing Paizo tends to charge for are pre-written adventures and, naturally, the beneficial formatting that comes with having a book with an index, rather than trying to search things on a volunteer-made pseudo-wiki.
That relationship goes on, but diminished, as one of the largest such sites—Archives of Nethys—has announced Paizo is terminating its partnership with it effective July 24. A post to the site goes into more detail: