I'm genuinely curious -- what do these recruits actually do while working these massive hours? Is there really 80-120 hours of desk-based work to be done, or does office politics or fraternizing play a role in those hourly figures?
On trading desk the analyst/junior guys typically will work like 6:30 through 7:30, which is not that much more than anyone else. They will be required to get lunches, coffee and other assorted errands. Again, this too is a form of hazing.
On the other hand, it amazes me how humans can do things that other humans consider insane. We're a flexible species, which I guess can be both good and bad!
There are various markets around the world that people trade in, and you are bound by the hours they are open -- unlike most coding activities. For example, someone where I worked had to stay up until 3am to participate in Japanese sovereign bond auctions.