It baffles me how you can call this convoluted process "learning". It's not. It's rightfully called the art of trivia bullshitting and has nothing to do with learning.
It's a purely social process that seems foreign and awkward to a visible majority of the HN crowd. I happen to agree with that crowd, I don't see the fun in it. I don't see the point in it. I wasn't raised to respond positively to this specific situation.
Instead - and again I believe a majority of the people on HN are in the same boat - I get socially interested in people with whom I can have exchanges that have the potential to affect the way I work, I behave or I see the world.
I have a fairly arrogant (but not necessarily incorrect) theory about this. I suspect that when you work/live in an environment which constantly stimulates you intellectually, you have an easier time getting to the "rewarding" part of more intellectual exchanges (eg. the facts of a conversation) than someone who works 9-17 at Walmart, and whose curiosity in the world is not being constantly nurtured, might. Thus we see a large majority of people who do not get any satisfaction from talking about more in-depth subjects than, say, Steven Tyler and Mary Tyler Moore.
And that lack of satisfaction is present on both sides. Once you have tasted what it's like to fire pure knowledge and experience at each other in a conversation and having all parties enjoy it, it's very hard to find any pleasure in exchanging senseless, bullshit factoids that will only serve to be repeated to someone else in the same social situation later on.