As much as I like reading and commenting on HN, I'm not sure I'd be comfortable socialising with opinionated geeks :)
To put all those people on one table certainly might help in exchanging different perspectives, but the conversation probably wouldn't have the same depth.
Or perhaps they meant that it’s a sign of youthful vitality and openness that they lost via the detriment of aging?
Thankfully it's possible to convince a smaller group to ignore them (don't feed the trolls etc) so you can have interesting conversations.