Looking at this from a federalist's perspective, how about these analogies.... You have a group of people who made and are sharing a common pie. One group, by chance, has the only piece with ice-cream on top, and they don't want to share it. Do they have the right to take away the best piece from the others? 
Or, you find gold under your land in a small town which taxes property based on its value. Should you be able to declare independence from the town and set up your own municipality to save tax money?
While there may be some legitimate grievances in this region, clearly, the separatists don't have a legitimate claim to the territory.