Duplicate discussions don't seem to be an issue (I see a lot of them, and someone usually posts a hint to previous discussions). It's also not an arbitrary "political" topic, but a request of recognised computer scientists to the Association for Computing Machinery. If everything would be flagged that anyone could get upset about, soon we wouldn't be discussing anything at all.

If a story has had significant attention in the last year or so, we bury reposts as duplicates. After a year (or so), it's fine, and that's why you're seeing links to previous discussions.

This is in the FAQ: https://news.ycombinator.com/newsfaq.html.