They do apply to HN, but HN is still very small compared to Reddit, and it's just one page dedicated to one (albeit) broad topic. The difference between Reddit and HN is HN has a reputation amongst a certain culture, so users fight to maintain their own reputation on here. How many times have I seen CEO's and founders of multi million dollar companies freely offer their insight on here? That's valuable, and for the most part, it's verifiable, and that matters to me, so I stick around here.
It's much easier to fling shit about a photo than it is about a very specific/complex product or technology. I can't exactly bullshit my way to top comment about something I don't know anything about on HN.
A lot of the users here, if you click their profile, you can find their startups, places of work, code they wrote, their blog, etc.
On Reddit it's a straight up free for all.