Well it can't because how can they check if you're licensed to play the game? Connect to the internet first, then it'll let you start the game.

Ironically, Xbox One support for true offline play was gutted when Xbox gutted a lot of planned Family Sharing support when Sony claimed the Xbox One was not going to allow you to play games offline and made that a marketing campaign with pawn shops like GameStop. (The same campaign that also called in-box Kinect a mistake and complained that the Xbox One was too "media focused" and "not for real game players".)

The resulting early Xbox One pivot removed features that would have been useful when systems were down and replaced them with "offline capable theater" instead. (The same pivot that also killed the Kinect and Xbox One multitasking and host of other useful media features.)