You can disagree with how it's implemented, but it's not subjective.
dang does a way better job of addressing moderation issues as they're happening than anything you'll see on Reddit (besides perhaps tiny, niche subreddits.) And at least he's not surreptitiously changing people's comments. (https://www.theverge.com/2016/11/23/13739026/reddit-ceo-stev...)
There are lots of other moderation features -- e.g. shadow bans and automatic vote penalties -- that are completely opaque but turn HN into a strong echo chamber.
I also disagree with your point about Reddit. At least on Reddit you can easily track what was removed (there are entire subreddits dedicated to tracking what's been removed by moderators) and many subreddits provide explanations of why content was removed.
Every time I click "vouch" I wonder if a counter is being incremented on my account, or if a record of things I've vouched is being kept for moderator perusal. A chilling effect which certainly exists outside of HN, of course.
There is. I've lost vouching privileges after the mods disagreed with my decisions. They don't tell you, either, you'll just notice one day that it no longer seems to work.
How is that a relevant comparison? Reddit is orders of magnitude larger (looks to be around 100 times more active users) and allows users to create public and private subreddits that can easily become echo chambers.
HN moderation is not even in the same ballpark as what Reddit deals with.
To be clear I'm not defending Reddit or even saying they do a good job; I'm just saying the comparison is not fair or useful.