No, of course I don't believe IT departments do that. It's management's responsibility to make sure someone is responsible for the data on every random PC on the network. Management is responsible for putting systems in place to manage risk effectively. Random PC users need to be compelled to comply by policy and enforcement because otherwise they usually don't have the knowledge or incentive to do what must be done.

People working in development or operations on the other hand, should instinctively know and do what must be done with their own data. And reddit didn't do that. Management failed and even worse the technical leadership inside the company was directly responsible.

Remember this next time you're working at a place with a poor management of data and a culture of indifference. Do something about it, sound the alarm instead of sitting on your hands waiting for the inevitable leak.