It’s an OOP technique, yes, but functions operating on structures predate OOP and are used in practically every program, so they’re not enough to claim that a program is written in OOP style without the term losing all meaning.

For me, true OOP requires some sort of inheritance and/or runtime method dispatch, at least.

OK, I'll go along with that. The description given doesn't contain a full "implementation" of what OOP is considered to be.

Can we at least agree that limiting operations on the structure to the code that controls that structure is following the definition of encapsulation, which is what I should have said anyway?