I've gotten a couple requests for Linux so far, and I believe it's a possibility, but I'm hesitant for a few reasons. Primarily, I don't know hardly anything about Linux and I don't have any Linux machines to test on. I'm extremely wary of taking money for a version of the game I'm unsure of and have no way of troubleshooting if there are issues. I'm sure y'all hear this a lot, and I'm sorry because I think the spirit of open source is extremely cool, but with my limited time and resources I don't think I can manage it right now. We'll see down the road!
To be honest, if you simply added a Linux build to the purchase with the caveat that it's completely untested even that would be a great step. Then if it works out of the box the problem would be solved, and if not then no big loss 😄 I'll also add a +1 to the number of people who'd be willing to debug should that be the case!
it's very easy to set up a virtual machine for testing, if that helps. no need to have an entire machine dedicated to linux. you may also find that technically-inclined players will be willing to help you troubleshoot problems.
I can understand your point and of course you're not obligated to support any particular platform though. I agree with the other poster that supplying an explicitly unsupported linux build would probably be good enough. I will probably roll the dice and buy the game, since another player said the windows version worked via wine.