I'm not sure why you are taking (or at least emphasizing) this interpretation; actually, the more relevant comparison (and one that has been made previously) is about the hubris of a superpower and the valiant sacrifice (for a principle) of a small group of independents.
To quote Tom Holland's Persian Fire, which is the narrative historical analysis of the era (well, this is the marketing blurb on the back cover):
About a hundred years later, at the end of the Peloponnesian Wars (with the Spartan hegemony against the Athenians), the Spartans borrowed money, equipment and men from a Persian satrap (in the modern Dardanelles, where the Athenians had a strategic base of operations for their food supplies from the Black Sea). It seems that the idea died with those martyrs ...
As an aside, the Spartans were regarded as peculiar by the other Greek city-states not because they had slaves (everyone did), but because they had Greek slaves (the Helots were neighbours they forcefully indentured). That, and Spartan women were equally as free in society as the men (and no chores to do, so they were more administrators of the household).
Fixed.