There was a post upvoted highly at the beginning of this current war, by scholar opinions about the situation in Palestine but it was removed completely, not just flagged or deleted. But full removal which I've not observed before on HN.
Barring some rare bug, I can say for sure that didn't happen. Posts on HN are never removed completely, except in cases when the person who posted it asks us to, and even then usually only if there weren't replies. Other than that, the most that happens is that a post gets killed, a.k.a. [dead] status, and any user who reads HN with the 'showdead' setting turned on in their profile can see those.
I'd like to know which HN post you're talking about, so I can say exactly what happened. Whatever post it was, it wasn't from the site opiniojuris.org. The most recent HN submission from that site was 10 months ago: https://news.ycombinator.com/from?site=opiniojuris.org
I respect that you've commented. It was something I upvoted. I checked through my upvoted submissions at the time and could no longer find it which was a first for me as either would expect it to have been flagged or deleted but shown.
I remember being a little shocked when it was on the front page and shortly after was not. I've checked again from <4 months. Wonder if anyone else can recall the URL - I just remember it was a collective scholarly opinion with condemnation on the situation, it may not have been from opinionjuris but the article was very similar.
I'm pretty sure that the code that decides whether or not to display a [dead] post doesn't consider whether the user had upvoted the post before it became [dead]. Maybe it would be better if it did.
Edit: I can't even click the link on the post you mentioned. Is that normal? That seems especially suspect and somewhat closer to censoring opposing views than I've come to expect from you and HN, Dan.
I don't know but if I had to guess it's because some of these links could be abusive/harmful or spam. I don't think it makes much difference practically in the cases that they aren't since then it's not hard to recover the link with the info left, if you wanted to.
It doesn't address the specific thing but you can see the broader logic here:
It was something like this https://opiniojuris.org/2023/10/18/public-statement-scholars...
HN claims they are different but they sensor more than Reddit, where at least have to be astroturfed with a majority.