> HN doesn't seem to have the same issue (at least not to the point it dominates the character of the platform), despite it being essentially a clone of old-school Reddit.

That is because PG sets clear rules and actively experiments with techniques to keep HN’s integrity intact, and since HN discussions are usually of the more intellectual variety, it’s harder for shit-posters and bottom-feeders to find traction here with low effort comments.

If you want to read his thoughts, check out his essay: http://www.paulgraham.com/hackernews.html