Yeah idk why, maybe cause it doesn't have a strong single player component.
Anyhow its a mix of rts and a rpg. Have you seen or played Dawn of War II? Its similar to that. You choose 1 of 8 demigods to play as, then enter a the match. The objectives range from killing other demigods to destroying the enemys base(citadel) As you play, you level up and unlock new skills and become stronger. There are soldiers that spawn from gates that move in pre destinated paths, so you cannot control them, but the more you have the better it is. My favorite character is The Rook. Hes like a giant statue/pawn, that has 3 towers from its body. You can learn skills to change one tower to shoot arrows automatically, one to shoot lightning, and one to shoot a trebuchet. The game is really fun, but its ment to be played as a multiplayer game, because there is no tutorial or really single player campaign. There is a scrim/tournament option for offline play which I am fine with and like to use, but for the real fun you'll have to use hitachi to join other pirates games.