Yeah, it's unfortunate, because for some reason, it just feels like games like GalCiv2 and Elemental would fit perfectly with Linux. I don't know why, I can't put my finger on it, but it's just like they resonate with eachother, the same spirit, the same kind of soul.
Linux users, generally, like to tinker with their computers. This probably also equates into being strategy-oriented as well.
Even though it's not supported, it may be possible to get it to work (almost anything is possible with linux, it seems). I read an article where someone got Sins of a Solar Empire working on linux.