Some people in this thread sound like they haven't run into contracting that much...
There's a whole spectrum of contracting, it can be "we need an admin to answer the phones on Friday, Betty's taking PTO" to "we need an PhD for 4 years and we don't care what it costs."
From the article, this sounds like something in the middle. The lines can get very blurred, so I understand how it can be misunderstood.
In essence, while technically employed by the contracting house (many times called a "body shop"), he was mainly an Apple employee. Apple badge, Apple boss, Apple hours, some Apple bennies (the bus, cafeteria, but not 401k, PTO, etc).
Apple would like this arrangement for a few reasons:
They don't have an employee added
They can let that person go immediately if they don't like them or demand slows
They can pay this as an expense and other financial reasons
Basically, it's low risk for Apple, and it's also called "try before buy" as good people brought on this way can many times become permanent.
Note, it's not really a cost savings as the body shop can be taking well over 50% of the pay rate as... well, tribute. LOL. Plus contract people are paid fairly well as the assumption is that this sort of work is temporary, and generally they get no benefits from their true employer.
In this sort of arrangement, you might have a pretty hard time separating out a permanent employee from a contract worker. Same goals, same boss, using the same systems, etc. There does have to be a veneer of difference though as the IRS (here in the states anyways) will look to see if they really are being treated as an employee. But this veneer isn't usually all that thick.
So, it's not uncommon to hear "oh you're contract? I thought you were permanent" or even the opposite "I thought you were contract" in these sort of environments.
Bottom line, sounds like this guy had visions in his head, didn't understand the relationships involved (his Apple boss was his boss, yes he could have gone to Apple HR, they'll listen to complaints), and he didn't like how all the sudden his days, which were fairly open, went to being dominated by his employer. Yeah, that can be a shock but if he would have been a bit more cognizant of what role he was playing, he could have parlayed that into something more down the road, but that this point all he's done is burn bridges - publicly.
Now, having said all that, I've heard Apple is a tough place to work, they work you hard and you really don't get even a clue as to what's going on around you due to secrecy. That's probably not all that fun - the most engaged I've been is when I knew what was going on, I knew how to help and I knew how to contribute.
Note: I've been a contractor, I've hired contractors... Been there, done that.