[labawi]

(1) IFF is shorthand for "if and only if". Try to read the original sentence, it makes perfect sense and is used correctly.

(2) Logically, iff, equivalence and double implication are themselves equivalent, the expression in question is (necessarily) logically correct even in those forms, though it is irrelevant as of (1) and a confusing way to express the relationship, as the causality clearly flows in one direction.

(3) It was not meant nor interpreted as a bare logical proposition, hence it is improper to blindly apply logical transformations and reinterpret in a different system.