I've been reading Herodotus for my Shimer classes and one of the things I was struck by was the description of the Persians as practicing the kind of rough and ready ascetic lifestyle we generally ascribe to Sparta. 300 portrayed them as indulgent and soft... quite a strange inversion if you view this as an allegory for the current situation.
Dude, you're missing the point of 300 -- the movie deconstructed itself! The Spartans' patently unfree lifestyle was exquisitely examined, to the point of violent child pornography. The Spartans' battle plans were held hostage to an unaccountable religious sect which was corrupted by both flesh and cash, and the Spartans themselves were tremendously poor compared to the Persians. The Spartans murder a group of unarmed emissaries. Leonidas' defense was undone by his heartlessness toward a devoted putative subject, who would have been killed at any rate under Spartan law had his parents not fled.
And this is a fight for freedom and civilization? No, this is a fight, period, between two peoples who are capable of both great nobility and terrible foolishness. 300 isn't about any sort of allegory; it is about the lies we tell ourselves in day-to-day life in comparison to the clean loyalties associated wtih battle, and why one might prefer the latter to the former.