The discussion on printed pages 320–321 considers whether comprehensive or general readings arise from the grammatical form alone. The circumstances of address can make an expression refer to a class or a quality without creating an exhaustive claim about every imaginable case.
When rhetoric contrasts two categories of persons, it need not assert a formal universal about all their actions or all possible objects of knowledge.
The important analytical distinction is between nonrestriction, universality, and contrastive characterization. The rhetorical purpose in context governs the interpretation.