That's like saying a gardener shouldn't worry about weeds because those who don't like them needn't look at them. The trouble is that if one allows such discussion, it spreads and takes over. It doesn't just stay static. Worse, it has feedback effects. For example it drives away users who find such rhetoric boring and lame, and attracts users who enjoy heated repetition. We want the first group here more than the second, because the first makes HN more interesting (higher signal) while the second makes it less interesting (higher noise).

We can't be passive about such effects. They can quickly develop into a vicious circle that destroys the site. HN will only survive as an interesting place for thoughtful people if it avoids that, so this is an existential issue and why I (we) moderate that way. I'm sad you think I've destroyed Hacker News, but would submit that if moderation doesn't evolve as a community grows, one ends up with the default dynamic of internet forums: decay followed by heat death. HN was actually started as an experiment in avoiding that dynamic [1], so in my view we're aligned with its original spirit when we do this. "Our hypothesis is that by making a conscious effort to resist decline, we can keep it from happening." [2]

You're right that the threads about global warming are almost as repetitive. The same logic applies to those.

Really though, if you want to make a case about the quality of the site, you shouldn't be posting things like https://news.ycombinator.com/item?id=20419652.

[1] https://news.ycombinator.com/hackernews.html

[2] https://news.ycombinator.com/newswelcome.html