The word "all" is a generalization referring to many. Alternate translation: "Now many of the Athenians and the strangers living there" (See: [[rc://en/ta/man/translate/figs-hyperbole]])
Here "time" is spoken of as if it were an object that a person could spend. Alternate translation: "used their time doing nothing but either telling or listening" or "were always doing nothing but telling or listening" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The phrase "spent their time in nothing" is an exaggeration. Alternate translation: "did not do much but tell or listen" or "spent much of their time telling or listening" (See: [[rc://en/ta/man/translate/figs-hyperbole]])