However, don't extrapolate this to a 'normal' undergrad's experience at Oxford.
I've never worked as hard in my life as for my MBiochem finals at Oxford - my law conversion is widely depicted as being intense, but didn't compare.
If the author of that article truly believes oxford tutorials are about defence, he's getting shortchanged, or he's looking to them for exactly the same thing our ruling elite gets from them; either way, he's shortchanging his readers in giving voice to such a view. The true aim of a tutorial is not to spend an hour defending what you wrote two nights ago, it's about letting that stuff fall into the backdrop to a cutting edge discussion with a leading (often foreign) academic; not just getting a better picture of what the cutting edge is, but where it's likely to develop to and what could be investigated over the next few years so we can get there. In UK undergraduate education, my understanding is that this focus on developing questions and probing soft spots in knowledge, rather than just assembling and defending answers, is pretty radical. And it certainly seems to run contrary to a fair amount of the article's claims.
Admittedly most of a tutorial's exchange of ideas flows to the student, but I rarely met a tutor who won't admit to having got something out of tutorials they have given, too.
Oh, and most of this article about Oxbridge is complete crap. I'm working 10 hours a day for 6 days a week in order to prepare for my exams this term at Cambridge, and I'm one of the lighter workers (including English/Classics students). I've never been offered sherry (though I did get some wine at the end of last term), and the interview process is nothing like he described. It's bloody intense. I had 2 interviews and 2 tests in a day and felt like I didn't answer a single question correctly.
As someone else mentioned, if prospective applicants take this article at face value they're in for a nasty shock.