I guess this issue isn't as hot as it was way back when the Supreme Court ruled on Citizens United v. Federal Election Commission, but its still an issue some people feel strongly about, and I happened to be bored today and did some google searches about corporate personhood.
Why exactly is it that corporations are people? In most legal systems only people can be sued, so if a sole proprietorship or a partnership causes damages, you can sue the owners. However a corporation is different in that the owners are not liable for any damages. So owners couldn't be sued because they weren't liable, and corporations couldn't be sued because they weren't people, so what were people to do? The courts of many countries eventually created the legal fiction of corporate personhood, so that they could be sued.
Now the important thing to remember is that even though they were legal persons they were not granted all the same rights as natural persons, they usually only had a few legal rights, "the right to a common treasury or chest (including the right to own property), the right to a corporate seal (i.e., the right to make and sign contracts), the right to sue and be sued (to enforce contracts), the right to hire agents (employees) and the right to make by-laws (self-governance)." Just enough rights to do business transactions and be held accountable for them. And that sounds like the type of corporate personhood that I can get behind.
Unfortunately corporate rights have expanded greatly in many places in the world, most notably the United States. In 1886, Santa Clara County v. Southern Pacific Railroad, the supreme court ruled that the equal protection clause of the 14th amendment applied to corporations, and was the first of many rulings where corporations would be granted rights found in the constitution. The most recent ruling of this nature was the aforementioned Citizens United v. Federal Election Commission, where corporations get the same free speech rights as regular people, and money = speech.
So basically corporate personhood was just something made up so corporations could be held liable, it wasn't intended to give the same rights as real people. I don't see a problem with corporate personhood if the rights are limited the way they originally were, however there is no reason why corporations should have any more rights than that. They aren't really people its just a convenient abstraction to treat them that way for certain legal procedures.
source: several wikipedia pages. No doubt someone will comment telling me how its not a reliable source.
It's obvious that guns are the work of an omniscient creator, how else would they fit perfectly into the human hand
-Stephen Colbert on the topic of god given second amendment rights.