What do you think user interfaces are? User interfaces are how users transmit or recieve information. Any information display is a user interface. Any button or other control is a user interface. There are even user interfaces that don't have to do with computers, like the user interface of a book (among that being its cover, pages and the information written on them). I don't see a single image here that doesn't contain a user interface.

The acronym 'UI' as typically used in computing often refers to specific types of user interfaces. That is not how TFA uses more generally 'User Interfaces', which practically covers anything that exposes information to or receives information from users

Inaccurate. Every one has a UI.