I personally like Tau entirely because they are the most altruistic and well-meaning of all the races. They do not exterminate other races, and they care much more about their own people than, say, the Imperium.
It isn't just me who thinks that the Tau are a beacon of light in a dark universe. Many Tau players have a similar point of view. In the 40k universe itself, There are many imperial citizens who are secretly sympathetic to the Tau. Even some of the strongest in-game Eldar leaders (Eldrad among them, I believe) say that while the Tau are young and naieve, they also are represent a new hope for the galaxy.
So ya. The appeal of the Tau Empire in part lies in the very thing you dislike about them: They are upbeat.
Last edited by Platypus5; 04-15-10 at 05:43 PM.