This is what I'm getting at. I don't believe most people are so laser-focused on a single one task that they have nothing else to do but read HN. If you have one and only one thing to do, you still might as well attempt to complete some facet of it. If you really can't find things to fill your time, perhaps you have a different problem. I don't see how reading HN is less frustrating than reading documents. It sure makes a nice excuse, but it's nothing more than an excuse to waste time.
Maybe I don't get it since I have a BigCorp job, but I've always got tons of little things I can do, if/when I want to. That sure seems like significantly better use of the companies time. Making the argument that "well this shouldn't happen!" is hardly solving any problem.
Interruptions are a fact of life, embrace them when they can't be avoided.