It is clear that perverse incentives exist in some industries, and that those industries have failed to self-regulate. They now need regulation forced upon them.
Luckily, in the UK, we have the European Working Times directive, and so interns should not feel forced to work 70 continuous hours.
The problem lies not in the rules, but in their enforcement.
I can't speak for the UK but in France it is not allowed for an intern to work more than 40 hours a week under any circumstances, yet in many industries you still see 60+h workweeks as a standard for interns...
Because by any means, an intern subject to this kind of unacceptable working conditions will not speak up since that would annihilate his chances to get a job at the end of his internship (and might even discredit him at other companies in the same industry)
The guy says that he wasn't doing any work. He was just a warm body.
Thus "You'll have to be at your desk for insane hours. You won't be doing much work. You increase the chance of fat-finger[1] errors. We know you'll probably have to take illegal drugs to stay awake that long. We're borderline illegal. We're opening ourselves up to serious legal liability (eg, causing harm to our workers). But hey, you'll get a shitton of money. (Where shitton is not that much, and less than you'd get from other more normal jobs)"
It's a perverse incentive because there's money slopping round in banking, and there are not adequate controls on how that money makes its way from A to B to C.
The bank does $SOMETHING, and the customers are happy and pay, and the bank pays $BONUS. But there's randomness in the system and often the $SOMETHING has very little to do with actually making any money.
The guy says that he wasn't doing any work. He was just a warm body.
Why do you care? In particular, why do you care enough to force the employer and the employee into a different understanding?
People do all kinds of things that I don't want for myself. I wouldn't want to be a boxer since I don't like having people punch me in the face repeatedly.
Doesn't mean I would want to forbid others from being boxers.
Let people have their freedom and stop trying to control everyone else's lives and choices.
Luckily, in the UK, we have the European Working Times directive, and so interns should not feel forced to work 70 continuous hours.