The IT department has no idea what kind of password that user was using, and they have no idea what kind of valuable data is on that machine. If that user's password was just "password" (or sticky-noted next to the trackpad), that IT department is going to get in serious trouble once all that proprietary data ends up in the wrong hands, if they didn't wipe the machine before handing it off to a third party.
If wiping the machine before getting rid of it is "extra work", then that IT department isn't doing their jobs to begin with. I'm certain such IT departments exist, but that's not enough of a reason to make theft easier.