The difference between Sparta and the Persian Empire is the Spartans SUPPORTED their own government and chose to follow it. They could have left anytime they wanted to.
Few if any did.
In Persia, all autocracy was imposed from above by an absolute monarch who conquered other people and other lands.
There is some truth in what you say, but the differences between life as a Spartiate and a Persian subject were cosmic.
Another admirable thing about Sparta was its cult of courage and patriotism. We could use an infusion of that.
And when judging another society using contemporary values, you are treading on unstable ground.
Spartan support for the Spartan way may have something to do with the fact that they were indoctrinated with propaganda from birth and really didn’t have much of a choice. Ultimately though the Spartan system destroyed itself.
By all rights, the average Persian subject was more free than their Spartan counterpart. Sparta existed on the backs of Helot slaves, who coincidentally were not to immured of the Spartan cult of masculinity.
Even by the standards of Sparta’s contemporary Greek polises, they were barbaric. Certainly the other Greeks admired their military prowress, yet there was equal criticism and no one wanted to replicate their social system.