You really think so? I think discussion and moderation is consistently good. Perhaps the 'SF bay mainstream' is more just a reflection of the HN audience in general?
Now minority opinions, even rationally expressed are just downvoted, which discourages writing them at all.
I think HN is slowly losing ability to have a discussion with people who hold different views. Now it is "my votes are stronger than your votes". Which is sad. Mt 2c.
For sure things have evolved, but this site and community is still working afaict. I suppose it depends on what minority opinions you’re referring to.
I will admit I would sometimes feel compelled to downvote minority opinions instead of refuting them. On some subjects (eg abortion), I have seen the same opinions and arguments made for decades. I'm tired of seeing the same poorly thought out arguments again and again and again and again.
However I try to hold back and just ignore those comments these days. (Not always successfully..)
0: I use HN exclusively on mobile and the downvote button is too easy to press accidentally, so the privilege is actually a curse.