It's ironic. We're all about disrupting and innovation except for our own sacred link sharing site. The answer you will get every time from these guys: Its good enough. Some perspective: Its 2014 and HN isn't mobile friendly #wtf
OR maybe it's essentially a hobby site written to justify an obscure and difficult to wrangle Lisp dialect that only a couple of people ever work on, and it's literally not worth the time for at least one of them to tweak.
I think dang has mentioned they're working on adding some stuff anyway so... who knows?