Be very careful indeed about drawing conclusions about corporate personhood from the manner in which it was achieved. For example, from the comments:
1886 Santa Clara County v. Southern Pacific Railroad Company, the Court granted Constitutional rights for the first time to Corporations and created the concept of corporate personhood. largely based on the fourteenth amendment which was meant to protect freed slaves
Interesting but irrelevant. For every legal system has ended up in pretty much the same place concerning such personhood. Whatever the background to the legal system or the specific events that led to the definitions.
The point being that the purpose of a company is to produce a legal person. That’s what the underlying idea is.
Natural persons, that’s us human beings, have certain rights, we most assuredly do. One of which is the right to be represented at law. We can be charged, we can charge someone else, we can enter into a contract, we can be held to the terms of that contract. My cat(s) cannot enter into contract, nor held responsible, at law, for anything. They are not natural people – despite, obviously, being the rulers of all they survey.
So, when we’ve got this grouping of people who want to undertake some task that grouping does not have any legal rights. It cannot sign a contract, cannot be sued under it, is not responsible before the law for anything at all. At which point we invent the concept of the legal person. This is something, someone, who is not a natural person but who also has some of the rights of a natural person. Including that most vital one we invent the concept for, being an entity which has a legal existence and can thus partake of the law.
Without corporate personhood it’s not possible for a company to sign a contract, nor can it be sued under one.
A legal person does not have all of the rights of a natural one. Or not necessarily. Citizens’ United was about whether the political free speech rights of a natural person extend to a legal one. The SC decided yes. The free movement of companies across the EU is because the EU itself decided that legal persons should have the same rights to free movement as natural persons. Either decision could be read the other way and we’d not have changed the basic underlying point – legal personhood exists so that companies can sue and be sued.
It’s entirely true that different jurisdictions have reached this point by different paths. But the path is not the important point about it at all. Some formulation akin to being a “legal person” is necessary to the very existence of a corporation in the first place, the ability to sue and be sued at law. Which is why near every jurisdiction has the same end result, whatever the path.