>And if you think there's a definitional difference between a government, a corporation and a mafia that stands up to any objective measure and isn't based entirely on social cues and special pleading,

If we're speaking of democratic governments you usually get to vote (whatever ineffective). And if we're speaking for non monopolistic corporations you also get to buy from another. With mafia there's a single, non-negotiable, option: the one running your area.

And both for goverments and corporations, there are other parties (e.g. courts) limiting what they can do.