As much as I like Linux, I think a Linux version should not be one of their priorities... at least, for now.
The thing is, the mod is still in alpha. As far as I know, they have to hook into the game's memory in order to implement multiplayer - rewriting the code just because Linux manages memory in a different way (that's my guess) would just be a waste of time that could be used to implement new features in the Windows version.
There are way more gamers using Windows - that's a fact.
And then there's testing for compatibility between different distributions... yeah, in my opinion, not the best idea now. Maybe once the Windows version is fully ready, but definitely not now.