Ah, it looks like that was a lost bit of code that somehow managed to stay in the game. They aren't really necessary, since, compared to all the other hoplites in the game, the Spartan hoplites already have higher hitpoints, intiative, logistics, and maxed out heroics.

If you do want to play with the Spartiates, you can spawn them by opening the console with the ~ key and typing:

addbrigade spartiateshoplitebrigade

(This spawns them in the middle of the screen, so you need to be looking at an open field.)

They are fairly over-powered.