The article you linked to is, I think, a little misguided. If I heard "the government are killing people" I'd assume it meant "the people who make up the government have collectively decided to kill people", which is really no different to "the government is killing people". The collective decision of a group is the individual decision of the entity that group represents.
>In [British English], collective nouns can take either singular (formal agreement) or plural (notional agreement) verb forms, according to whether the emphasis is on the body as a whole or on the individual members respectively; compare 'a committee was appointed' with 'the committee were unable to agree'.
http://en.wikipedia.org/wiki/American_and_British_English_di...
This is how most of the world does it, as far as I can tell, though in traditional Islamic law you only had business partnerships that dissolved if any of the members left.
There are various arguments against having authority reside in abstract entities rather than real people, but I hope you can see how it can be good in the case of democratic governments at least, like the City of London Corportation. http://en.wikipedia.org/wiki/City_of_London_Corporation
EDIT: To be more clear, pretty much all businesses are some sort of corporation, even though most people use "Corporation" to refer to publicly traded joint stock corporations. All non-profit organizations are also corporations. Some (but by no means all) municipalities are also legally corporations, but I'm not sure exactly what the distinction between that and other forms is.
EDIT2: Reading some more in Wikipedia, I might be using the word "corporation" too loosely in the above, and there are also plane companies and partnerships that are incorporated entities but not corporations, and have the same sort of legal person hood that corporations do.