This is an affront to democracy on at least two levels. First, we're talking about replacing the elected government of the 18th-largest city in the United States with an unelected bureaucrat expressly to undo actions undertaken by the elected government. Detroit's population is larger than those of Vermont, North Dakota or Wyoming. But Michigan Republicans are fine with—eager to—take democratic local control away from that many people.
Second, the law Snyder is using to appoint an emergency financial manager is a replacement for the emergency financial manager law that Michigan voters repealed in November. Just over a month after that repeal vote, Republican legislators passed and Snyder signed an overwhelmingly similar version of the law during their notorious lame duck session.
It's fitting, I guess, that if you're going to deprive around 700,000 people of their elected local government, you do so with a law nearly identical to one that had previously been repealed by voters. If you're going to act against democracy, you might as well double down. But the whole thing is appalling.