It definitely needs to happen. From my perspective the question is whether it needs to happen here on HN. The answer is yes and no, for the reasons I linked to above.
There's an interesting dynamic to this, btw. If HN manages to stay a degree or two more interesting than internet median [1], it attracts high quality users. That makes it a desirable audience. That makes a lot of people want to target this audience, so they blast it with rhetoric. Rhetoric isn't curious conversation and it thrives on repetition—so it makes HN worse.
In other words, to the degree that HN gets better, it gets worse. There's a cap on how good it can ever get [2].
My working theory of the eigentweet is that it's more internal than people "wanting to target this audience." I don't think it requires much if any outside influence or explicit bad faith. (I'm a moderator on a non-American political subreddit, so most of my opinions below come from my own observations and musings.)
Instead, the decay of social media happens as the platform transitions from a place where one talks with people to a place where one talks at people.
If I reply to your political thoughts by telling you off, I'm probably not trying to convince you to change your mind. Instead, I'm performing for the attention (and upvotes / retweets / kind comments) of like-minded peers.
That's obviously alienating for the person who gets attacked, but this kind of performance is also self-radicalizing. The validating reinforcement preferentially goes to the strongest attacks or defenses, favouring rhetoric (as you noted) rather than substance.
One of the few things that suppresses this cycle is exactly what HN does reasonably well: have the community be about something else, diluting political content such that there's less often a chain-reaction.
There's an interesting dynamic to this, btw. If HN manages to stay a degree or two more interesting than internet median [1], it attracts high quality users. That makes it a desirable audience. That makes a lot of people want to target this audience, so they blast it with rhetoric. Rhetoric isn't curious conversation and it thrives on repetition—so it makes HN worse.
In other words, to the degree that HN gets better, it gets worse. There's a cap on how good it can ever get [2].
[1] I'm not saying it's very good at this. But it's all relative, and what matters is outrunning the bear: https://news.ycombinator.com/item?id=25725436.
[2] https://news.ycombinator.com/item?id=16443431