[El Gato]

Corporations are citizens.

Not really, they have some "rights", but only as defined by law and subject to changes in the law. They do not have the right to vote for instance. A corportion cannot be incarcerated. In many cases even it's officers and managers are protected from legal consequences of their acts in the name of the corporation. Even the owners of the corporation, that is the stockholders, are only at risk for their actual capital invested, not for any damages the corporation might cause, nor for any debts the corporation might incur.

[Dog Gone]

Over one hundred years ago, the US Supreme Court ruled that corporations are "persons" and have can assert their rights under the Bill of Rights. A corporation, for example, has free speech rights and the right to a jury trial. By statute, they are also citizens of the state in which they are incorporated and where they conduct their principal place of business. This is important for taxation purposes as well as for establishing diversity jurisdiction in Federal court.

I'll agree that corporations are not equivalent to natural born persons and don't have all the same rights and obligations of real people, but it's pretty darn close.