But what does The Battle of Thermopylae have to do with with guns?
To the gun rights people it has to do with arms. However I would venture that it is actualy a very bad example of a people to highlight for RKBA.
They had an entirely slave population who they routinely terrorized to keep them subordinate and submissive. Had rights of passage that included sending young boys out into the night to kill members of the slave population.
Newborn babies were bathed in alcoholic wine to see if they were strong enough to survive it. If they did then they were eligible for inspection by the elders, who if they found any flaws put the baby outside for the animals to eat.
Men were fined for not taking boy lovers. It was expected that men be active pedophiles and mentors of a boy as it was believed to help create a stronger positive influance. Women were expected to do the same, though they were not legaly bound or fined for not doing it.
The men were very feminine by todays standards, combing thier hair before battles, engaging in bisexual relationships, etc which actualy probably was a major contributor in thier sense of duty and valor to eachother as they were emotional and physical lovers. They even excercised naked with oil for the sole purpose of being more sexualy attractive to eachother than without oil or wearing clothes.
However they were also extremely honorable. A famous example is this story:
"An elderly man was trying to find a place to sit and observe the Olympic Games, as he went to each section. All the other Greeks laughed as he tried to make his way through. Some ignored him. Upon entering the Spartan section all the Spartans stood and offered the elderly man their seats. Suddenly the entire stadium applauded. All the Greeks knew what was the right thing to do, but the Spartans were the only ones who did it."
All in all the very things that define who a society is and the values and family unit were different and unrelatable to modern society, so could not be accurately displayed and still sell to the target audience of guy movies. I would probably find it repulsive myself even enjoying the historical accuracy and portrayal. However the actual battle I would have highly enjoyed, even with some emotional theatrics.
Then there is the tactics. Spartans had very large shields, very different than those employed in the movie. This was a necessity for the tactics used by them and the formations they used. They did not charge in or run around like macho individuals as in the movie. In fact to do so would have been a serious dishonor to Sparta and fellow soldiers punishable by death and the man protected by your shield would have been exposed. The symbol fo the shield and its purpose was sacred to Spartans, even to the extent of being presented to them by thier wives upon leaving with the phrase "With this, or upon this" refering to the fact that no soldier should return to Sparta alive without his shield. This is because the very large shields were heavy and escaping while carrying such a heavy thing was nearly impossible. Also to discard or lose your shield meant you were not only a dishonorable coward, but you let down the fellow soldiers dependent on your shield for protection in formation. The Spartan Phalanx was the primary formation used for fighting, and is extremely dependent on everyone having a shield, however such a formation does not lend itself to theatrics and exciting screenplay, nor does such a large cumbersome shield.
Even the physical build of the men was innacurate showing predominantly large men with gym and weight lifting builds like a typical action hero, which in a time of limited logistics and days and days of marching was not caloricly possible. Most men of sparta were long and lean, carrying heavy gear many miles eating minimal food, just like many other soldiers of the time period.
So the entire thing is just a bunch of macho BS designed to appeal to such emotions. No different than many other movies, except that it is refering to real life events. I can enjoy a macho BS flick myself, however not when it portrays such a coveted military success falsely. There is not many such decisive extreme examples of military achievement so when they screw up one so severely it is unfortunate.
I imagine some people would feel the same about a fake fictional representation of the Alamo. It dishonors soldiers and men who died for something they believed in and were so successful doing so to falsely represent thier struggle when it is easy not to do so.