HN still seems to value constructive criticism though, to an extent that is simply not possible on YouTube.

YouTube comment section is basically a cesspool of toxic positivity now, with absolutely no informational value at all.

I feel like this has been the case for a couple of years now, where nothing even slightly critical will be surfaced by whatever automated algorithm they are using to filter/boost content.

Eh. I've seen it happen and it's really damaging to discussion. I now actively avoid some topics and let people believe whatever they want around a few topic where the community usually get it wrong, but actively resist getting corrected.

Thank you for writing that. I think both karma limits/day and a downvote limit/user need to be instituted to allow for respectful disagreement and useful conversations on HN.

Which topics are those? It doesn't take many downvotes/flags to kill a post here but for most issues there isn't a single hive mind and the result really depends on the thread and also time.