In the eyes of the law, a corporation is itself a person. This effects two sorts of things.
The first comes into play when the corporation is shared amongst multiple owners or ownership changes. Because the corporation may enter into contracts as a legal person, may be sued as a legal person, and may bring suit as a legal person, it is typically unnecessary to identify all the owners for purposes of contracts or of suits, and shares may be traded without explicit and complex contracts reässigning rights or responsibilities.
The second thing effected is limited liability. When a corporation is found to be at fault in some way, typically no more may be seized to satisfy its responsibilities than that assets of the corporation; other assets held by the owners are insulated from confiscation. (And when corporations are themselves permitted to file for protection as bankrupt, there may even be insulation of the corporate assets.)
It is largely because of this insulation that corporations are sometimes created to be owned by single persons, who have no intention of selling shares. (And those owners may be merely legal persons — corporations most of whose assets are now insulated by a layering of incorporation.) Unlimited liability presents some potentially enormous difficulties for the law when a company has many and variable owners; but, if such limitation is to be granted at all, any sort of minimum number to qualify for that limitation would seem to be arbitrary.
In the case of liabilities to second parties — those who have chosen to do business with the corporation — there is really no problem of morality nor otherwise of economics in limiting those liabilities. The limitations are essentially contractual conditions. (And, historically, some firms have avoided incorporation exactly to get the volume of business and to be able to charge the sorts of prices that a corporation within their industry could not.)
But liabilities to third parties — those who have not contracted with the corporation — are another matter.
An example of a liability to third parties would be a case where an airplane crashed into a residential neighborhood. The owners or residents entered into no agreement waiving damages, but if the assets of the corporation are not sufficient to make those victims whole, typically the other assets of the owners of the corporation are out-of-reach.
Incorporation confiscates the property of third parties. At the least, the right to be compensated in the event of injury is abridged.
Economic efficiency would require that an activity be avoided unless its expected value — that is to say its value accounting for possible outcomes and the various plausibilities of those outcomes — were greater than alternatives. For that to obtain, the activity must be fully insured (either self-insured or by the purchase of insurance through an agency); but, if a party is insulated from liability, then that party has a natural incentive to over-consume risk as a productive factor.
And let us be clear that corporations are a deviation from laissez-faire;
free-market corporation is a contradiction-in-terms. Incorporation may be on behalf of some private party, but it is not itself a private act. It is the state that creates corporations. In exchange for registration fees and perhaps for special taxes, the state implicitly confiscates the property of third parties, and enables the owners of the corporation to over-consume risk. Where the sums extracted by the state are less than the cost of full insurance, there is more incentive to incorporate, especially in the cases where the firm is to be owned by a single individual or by a small and stable group of people. And corporate taxes are not indexed to risk. When third parties are injured, officials of the state may present themselves as rescuers or as champions of the victims, but those officials are actually amongst the victimizers. And, since over-all the monies got from registration fees and corporate taxes are less than the corresponding aggregate cost of full insurance, either some third parties injured by corporations must go uncompensated, or taxpayers of some other sort must make good the difference.
When there's an argument over whether corporations are people, oftentimes each side is simply talking past the other.
Those who insist that corporations are people are not typically expressing a position on whether the law should create such legal persons; rather, they are usually trying to communicate that the burdens imposed upon corporations are ultimately imposed upon people — that nothing that the corporation is compelled to do can be done except that it be done by human beings, and that nothing taken from a corporation is not taken from its ultimate owners, who are people.
Those who insist that corporations are not people are typically arguing that the legal fiction that a firm is a distinct person is unwarranted.
But many of those who assert that corporations are not people go on to insist that, because corporations are not persons, they may be compelled to do things that persons should not be compelled to do, and may be restrained in ways that persons should not be restrained. However, it's one thing to argue that a corporation as such is not itself a person outside of law and should not be one in the eyes of the law, and entirely another to argue that the acts of corporations are not the acts of any person and that constraints on corporations are not constraints on any people. With the corporation stripped of distinct personhood, the actual persons of the corporation are revealed, not hidden. A willful blindness is then required if they are not seen.
In the face of decisions to which he objected about what was allowed and disallowed for corporations, Bernie Sanders asserted that Ben Cohen were a person and that Jerry Greenfield were a person, but that Ben & Jerry's Homemade Holdings, Inc., were not a person. But if, while Messrs Cohen And Greenfield still owned that corporation, the law had forbidden the corporation's doing such things as hiring the homeless or required it to do such things as to devote a percentage of its capacity to the manufacture of munitions, then this imposition would have forbidden them to do these desired things or required them to do these repulsive things, and they would surely have taken that quite personally. Ben & Jerry's Homemade Holdings was not and is not a person (outside of legal fiction), but it was and is persons and the property of persons. Mr Sanders is willfully blind or a demagogue or both.
They and Mr Sanders might be quite sure that what they wanted to do were right, and that what they didn't want to do were wrong, but so are the owners of corporations who want to support political candidates or who object to paying for abortifacients. Liberty isn't simply for those who agree with some of us; it wouldn't be liberty if it were.
It might be argued that the various constraints placed upon corporations are none-the-less perfectly legitimate, as incorporation were voluntary. But if incorporation creätes a relative advantage for those who incorporate in some industry, then it ipso facto creätes a relative disadvantage for those who do not. Incorporation may then be voluntary only in the sense that participation in that industry in the first place is voluntary. In such a context, insisting that those who incorporate have voluntarily surrendered various rights would be analogous to claiming that carpenters have voluntarily surrendered those same rights.