If the wisdom of the classics stopped being applicable to modern times then they would die out and stop being read. So, only the observations remain that are most stable, general, and enduring over time.
The power of the classic is largely in being pliable enough to be read in new ways by successive generations, if taken litteraly Plato obviously has nothing to say about downvote etiquette.
He doesn't make even a single throwaway comment on the process of throwing black or white potsherds into an urn to decide whether someone shall be banned from the city of Athens, i.e. the original meaning of ostracism? Because AFAICS that would be pretty literally (actual literally-literally) about downvote etiquette.
