You judge each comment by its own merits. Online forums like HN are a source of ideas, not necessarily correct ideas.

Eh in many ways that is not how humans work. We tend to build close in groups with higher trust level, because not trusting everything any anyone is physically and mentally exhausting. If you met a person that behaved in this manner in real life most people would conclude they had a mental illness or were an abuse victim.

Interacting with accounts in a huge, pseudo-anonymous social media sites based on discussion with voting systems is quite different from interacting with people in real life. For big sites like HN and most subreddits, the users may as well be anonymous. HN goes a step further and deemphasizes usernames a bit by making them lighter in color and smaller compared to the black body text. How do you build a "close in group" on a site this big with not a lot of emphasis on who you are? I've been on smaller message boards where you can actually get to know people and have an avatar and some public info about yourself attached to every post. It's a different experience in that case, for sure.

You wanna talk about how humans work - strangers in real life also don't just walk up to you and start talking about Reddit account security out of the blue! We also don't trust a talking head on TV or on the radio just because they're human. Relationships are built over time & higher trust has to be earned. Even if you're referring to the fact that most of us probably live in a relatively high trust society, that doesn't mean we trust our neighbors' opinions on strong passwords (or whatever) just because we trust them as our neighbor!

It would be nice for everyone to achieve the platonic ideal of having a gapless empirical understanding of the world from root to stem. It is not possible for a single person to do that, let alone everyone. At some point it becomes necessary to trust if we are going to provide and consume information remotely.

Ideas do not exist without context. Arguably the context is more essential than individual ideas. Judging ideas without context is not a useful exercise. It's easy to fall into a local minimum that's actually quite bad. Eugenics is a common example. Eliminating genetic disease sounds great as long as you don't have the context of genocide or humanism.