You can't downvote articles so the fact an article has a lot of upvotes can't really be used as an example of HN being an echo chamber. All the people who want

You can't downvote articles so the fact an article has a lot of upvotes can't really be used as an example of HN being an echo chamber. All the people who want to downvote it have no voice. Plus, an upvote isn't really a mark of agreeing with the article; some people upvote because the article is interesting and worth discussing. Also, and maybe I'm playing to the echo chamber a bit here, it's possible that there are some subjects that HN readers are just mostly aligned on. That doesn't make the whole site an echo chamber. There are still plenty of things that HN can't agree on (JS SPAs is a good example - every thread gets split right down the middle).