anybody who has taken an introductory course in tort law knows that you will study, within the first two weeks of lectures, that corporate personhood arose out of a difficulty assigning fault in cases where the corporation as a whole is liable, rather than an individual. otherwise, no entity would have legal standing, and no court procedure could occur. this really comes right out engels - no one person can say "this product is mine" type of thing. further, it's beneficial to workers because it collectivizes the liability.
the logic used in the case is not hegelian but kantian; the judge tried to dumb it down by arguing in terms of christian ethics, but if you break it down properly you'll see it's a deontological argument built on a social contract, but proudhon's more so than rousseau's. the foundations of this tort law are actually just about the most perfectly anarchist thing you could possibly imagine arising out of the british legal tradition.
elsewhere, i've heard chomsky talk about how we give corporations rights but not responsibilities. that gets to the more serious problem. personally, i'd rather see limited liability abolished than corporate personhood, as it would reestablish disincentives against investing in environmental devastation & etc. and, if corporations are people, should they not be taxed as people?
but, this history is wrong. corporations are people because it's the only way they can have legal standing, and the courts have determined that they must face consequences for antisocial behaviour due to kantian considerations of a social contract. this is good shit. this is powerful shit. reform is necessary, but it needs to be more complex and subtle than merely abolishing personhood.
http://www.youtube.com/watch?v=abdnMJALp7k