I think most people still see Hackernews as a website for people in the software industry, where IC is common knowledge. Plus comments aren't written to educate or sell a subscription, rather they're to ask a question, continue a discussion, or contest some point, so it's natural for the writing style to lean towards the informal and be less patronizing. And of course the search you show is a great example of why this isn't too big a problem - since HN is a discussion board, if someone is confused and they can't find the answer on Google, they can just ask for clarification in the comments, often getting a reply from the person who made the original comment that confused them. With a newspaper you can't really do that - even in comment sections authors rarely answer questions, and other readers don't tend to engage with the comments unless they have reasons of their own.