Mondelez likely threatened Zurich with extensive lawsuits when they realized the companies were an order of magnitude apart (10 vs 100mm), and Zurich threatened back with their version of Judge Smalls -- you'll get nothing, and like it!
To a commentator below who doubted they could prove Act of War conclusively in court: they will never have to -- this would be a civil case, they only have to achieve "more likely than not," which may not be difficult given the extensive declarations, as mentioned in the article, from FBI, DoD, Pentagon, etc.