I’d say that’s a poor choice of words on the author’s part. Combinators like > and + certainly do cause a selector to target a smaller subset of elements in the page than the selector would without them, and in that sense they are more ‘specific’, but they do not contribute to the Specificity (with a capital ‘S’, meaning the formal ranking of CSS selectors that determines the order in which rules are applied to the document) of a selector.