HN is strongly anti-controversy. So when you have a large enough minority of users who rally around flagging certain topics, they easily get taken down even if there’s otherwise interest in the discussion. I don’t think it requires owner manipulation. You can see it in how things like any coverage of Palestinian perspective getting flagged immediately while coverage of far-right ancap politics lingers despite both being contentious political topics (where ancap discussion is controversial but detractors lack the habitual urge to flag brigade and are more open to discuss).