Umm, in many jurisdictions they are [almost]:
"In most countries, a corporation has the same rights as a natural person to hold property, enter into contracts, and to sue or be sued. Granting non-human entities personhood is a Western concept applied to corporations."
https://www.npr.org/2014/07/28/335288388/when-did-companies-...
https://www.purduegloballawschool.edu/blog/news/corporate-pe...
A person has rights other than to hold property, enter into contracts, and to sue or be sued.
Indeed.
In the context of this thread, how are those other rights relevant?
That a company isn't a person. We know this because a person has rights a company doesn't.
It would appear that this view is not widespread:
"In law, a legal person is any person or 'thing' (less ambiguously, any legal entity) that can do the things a human person is usually able to do in law – such as enter into contracts, sue and be sued, own property, and so on. The reason for the term "legal person" is that some legal persons are not people: companies and corporations are "persons" legally speaking (they can legally do most of the things an ordinary person can do), but they are not people in a literal sense (human beings)."