Developing anything for limited platforms today is folly. This isn't 1999 where the Windows market rules supreme and anything else is irrelevant minority. People buy computers and devices for convenience, and that includes everything they do with these devices (NOT just games). That said, developers should be factoring Tablets into the complete gaming experience as well, whether it is simply as a game-enhancement feature or developing a game in a way where part (or all) of the game can be experienced on a tablet client. For example, imagine that you could craft on a device client, so you could focus on more robust parts of a game when playing on your computer or console?
That said, ruling out one of the fastest growing computer and device markets is sheer laziness and demonstrates a disconnect with the consumer market. I don't care who likes or hates Macs, the fact is, they are growing in popularity largely because their iOS market dominates, and those devices integrate seamlessly with their computer platform. In the next decade, there is a strong possibility that if the market remains status quo, there will be a larger number of OSX users than has already grown in the past half decade, and it will be a percentage that challenges Windows substantially. If a game plans to still run its' client at that time (in other words, become a successful game), then it should be developed with present and future hardware trends in mind.
It's no mystery that some of the most successful game populations were built for both Mac and PC platforms. Food for thought. Bootcamp is a choice, but it requires Mac users to pay Microsoft's ludicrous pricetag for an operating system that they would use for nothing more than a game or two. Consider also that dual boot or virtualized Operating Systems eat up a substantial portion of the HD, and with SSD technology being the preference moving forward for improved performance (and SSD capacity is still quite limited compared to spinning counterparts), disk space currently is precious.
I prefer the OSX/iOS environment. I used to run Bootcamp, but I don't bother anymore partly for reasons listed above. Quite honestly, there is enough game variety available for the Mac to suit my needs whether through dedicated or a Cider Port client. Anything that doesn't offer an option doesn't get my attention any further than reading the system requirements (and posting my opinion on platform deployment on a forum

. I'm not the only Mac user that feels this way. I can live without a shiny new title in favour of something that supports my preferences.
I'm sure it's a wonderful game. Success will ultimately be determined by player retention and population. It's up to the game designers and developers to ensure they have a wide enough reach to make that happen for those of you who are very excited about this game.