They tend to get moderated away most of the time, which you can help by flagging them or emailing them to hn@ycombinator.com. Supercilious PSAs don't do any of that.
It's very common on HN. I do it too. Mostly because we spend a lot of effort avoiding these platforms, and when something bad happens to a person because of it, we can shout, "Ha! My paranoia is justified!"
If you're working day to day as an engineer, you end up mostly thinking in unhappy cases and 99.99% uptime scenarios, so it actually seems like helpful advice.