HN is an echo chamber when it comes to tech choices, but it's absolutely not when it comes to politics. I've seen many pro-Trump supporters in the ranks here, which is very surprising given the demographic.
Pro Trump articles (and anti Clinton) would appear on in the sea of other articles, but they were always black or grey within a minute or two of their appearance. Pro Clinton articles were about 50/50 throughout the day, some staying, some being voted off.
I attribute a lot of the lost articles to the feeling of "keep HN clear of politics", and a lot more to fringe/fanatical news sites making being flagged, but the overall trend of preferring Clinton to Trump was definitely visible. Bernie Sanders articles were ones which stayed up even longer than the others combined.
So, long story short, yeah, HN is still quite the political echo chamber. It's understandable: many of us share both general job descriptions and life goals; I'd hazard a guess that most even share an age group and fall within a handful of ethnicities.
When I read HN, I got the feeling, most political comments that get upvoted are phrased like "I know everyone here is a liberal leftist, BUT I have to tell you about my conservative right opinion right now, even if you don't wanna hear it!"
But I never really encountered these "liberal leftist" majority here. Just in places of the Internet that don't have anything good to say about HN.
Is the same 5 or 6 conversations over and over really any less of an echo chamber than 2 or 3?
I like to come up with my own conclusions, which may - or may not - be what my demographic group "expects" me to.