It may be a cultural thing, but I think many people see negative sentiment as a constructive tool and a demonstration of trust and respect among people who recognize each others as robust and capable peers.
Avoiding it is something you do with people who you believe need special delicacy: whether because they've told you so, because they intimidate you, or because you sense something pitiable and fragile about them.
If you can trust that it's given in good faith, and by the guidelines of HN you are asked to, negative sentiment should be seen as an expression that someone thinks you're a fully capable adult and peer. Personally, I deeply appreciate that it's generally so comfortably shared and received here and would never include "toxicity" in one of my critiques of HN.
It's a surprising thing to read someone say!
(Unless you're thinking of the nastiness that can surface on flamewar topics, but there are numerous means by which those get downranked and displaced, and they're otherwise sparse and easy to avoid.)
