Billionaire "Commonwealth" Scheme Is Unhinged, Un-American Radicalism

If Belle Isle could be extracted from Michigan to form a tax-free Puerto Rico-like "commonwealth," then why couldn't other parts of the country secede from their respective states? The greater San Francisco Bay area could leave California and form a territorial government based on the governing structure of an organic food co-op. Mississippi could simply renounce its statehood and form a territory where a poll tax is allowed. Clearwater could leave Florida and form a theocracy built around Scientology. For that matter, why couldn't a group of unhinged left-wingers form a territory on vacant Detroit land and implement Pol Pot's agrarian policies within its borders?