How many IRC channels have you hung out in? Every channel I've ever been in with any sort of community has stuff like this pop up pretty regularly (things that may be "off-topic" by some definition, but are interesting, and spark some interesting conversation).
Channels where there are hard and fast rules about keeping the discussion strictly "on-topic" don't tend to be channels I hang out in. The same would be true for HN.
Any IRC channel I've been to that develops into a community spends 90+% time talking about everything else except the topic it's ostensibly about. It's weird from the POV of the newcomers, but for old-timers, most of the on-topic things were talked about to death many times over already.
How many IRC channels have you hung out in? Every channel I've ever been in with any sort of community has stuff like this pop up pretty regularly (things that may be "off-topic" by some definition, but are interesting, and spark some interesting conversation).
Channels where there are hard and fast rules about keeping the discussion strictly "on-topic" don't tend to be channels I hang out in. The same would be true for HN.