Since this isn’t a traditionally blacked-out topic, I dig around a bit and I believe I found the cause. I archived it here. It’s an opinionated essay for sure: https://archive.ph/UA7aD
I’m not saying I agree or disagree, but I can’t get on board with the suppression of discussion.
Do you links to the accounts/posts being killed?
1. The link itself caused the comment to be auto-killed. This can happen when you link to particular sources (I've demonstrated it in the past with, IIRC, a UT subdomain that had ended up in the spam list somehow, mods corrected it).
2. The fact that a new account with low karma submitted a link caused it to be killed. This is very common, they get caught up in the spam filter (which doesn't always look at the link content, but at the account behavior). New account, one of their first comments includes a link, often spam.
Email the mods, link is at the bottom of almost every page on HN, if there's nothing wrong with the link (and it looks like there isn't) then they'll restore the comment and account (if it ended up getting shadowbanned).