What is being described is that people will know what they're talking about, which is debatable. You might be corrected on here, but I've seen more cases of people being loudly wrong but having enough general knowledge on a subject that they sound correct, and lucky enough that no one with specific knowledge stumbled on their posts to correct them.

Frankly, I don't think hackernews is all that different in terms of community from Reddit. People are just better at hiding it. Many are regurgitating rhetoric they've heard in other posts without having experience with a subject. Even in the realms of programming, it's not hard to see how little experience people have with the things they demonize or evangelize.