Usually VDH makes a great deal of sense. Can't figure this one out.
At the Hot Gates the Greeks lost something less than 2000 men total. How this works out as the greatest defeat in the entire history of Greek city-states is beyond me. The Athenians lost something over 35,000 killed in their ill-starred expedition to Sicily alone, and Athens and other Greek city-states had plenty of other disasters in their history.
He's possibly referring to the sacking of Athens after the battle.