Boot your Mac in windows or something.
But seriously you don't expect that companies will develop games for Mac, do you? Although nothing is wrong with Mac hardware or OS, but do you really think that a game company, espesially indie one is going to use money, time and resourses to port a game to a system that only a small percentage people use? And the fact that most gamers don't use mac at all, makes it even less atractive to make a game for one.
As for Linux support, I have to laugh there. Do you expect that any game company is going to make patches for every distro out there?
Personally I would rather see developers to use their time to make patches, or expansion packs instead of porting to every system out there.