I imagine posts go off-topic because people don't know anywhere else to post their thoughts. I've often seen posts where people wanted a Hackernews for X topic,

I imagine posts go off-topic because people don't know anywhere else to post their thoughts. I've often seen posts where people wanted a Hackernews for X topic, but none exist (apart from maybe Reddit). The old forum meme of 'posting in the wrong thread' doesn't really apply on HN. On the other hand, if the topic drifts into political flamebait and outright propaganda, people deserve to get down-voted and called out.