You're correct, the sync client is not currently available for Mac. As a Mac user, I feel your pain. I saw that you voted up the idea, so thanks for doing that. I believe our devs are working on a solution for automated extract refresh on mac but there are currently no specifics or dates set:
Thanks for responding. I would only think it would be obvious to have the same functionality for Mac. After all there are a lot of people using Tableau for Mac. Because there were issues with high res scaling using options like bootcamp and parallels, IT set up a virtual machine for me and I installed Tableau for Windows on that virtual machine and set up extracts to refresh via the online sync client on that virtual machine and I run Tableau for Mac for my daily need. It works pretty well for the most part.