Earlier quoted context omitted.
So you take the replies to replies from a single thread, and conclude that the site itself is useless? I suppose I should discount Stack Exchange, as there undoubtedly questions for which all of the answers are unhelpful or incorrect. Your comment reeks of the typical reddit hate on HN, without anything to back it up.
I wouldn't say the entire site is useless, but the good communities are few and far between due to the reddit's culture abhorring any sort of moderation. Would you like me to edit my reply to be more specific to /r/AskReddit? Certainly if you have a scientific question, /r/askscience is great, and /r/philosophy tends to be decent most of the time. But my point is that getting honest, relatively troll-free discussion…
The fact that something is frontpaged greatly decreases the signal to noise ratio, the moderators are IMHO asshats.
Do some searching to find topics that interest you, and then unsubscribe from every single front page subreddit. You'll have a much better experience as a result.