Generality and absoluteness answer different questions. A general term concerns inclusion of every member within a class; an absolute term concerns whether a particular additional quality has been required of the thing to be supplied or performed.
“All students” includes everyone in the stated class. “A book” calls for a book without a stated color; “a red book” adds a qualification. Fulfilling an absolute demand normally requires one appropriate instance, while a general ruling can apply to every relevant individual.