Why? For the same reason any story floats to the top. We are clicking through to read the linked article, up voting, and (like you) participating in the discuss

Why? For the same reason any story floats to the top. We are clicking through to read the linked article, up voting, and (like you) participating in the discussion. Put all this stuff together, and the story will trend highly for a while. HN doesn't have the kind of purity filter you are looking for.