Hacker News is almost indistinguishable in spirit from a well-run subreddit. Reddit is not centered on user profiles and followers and yet, Reddit is included in the Australia's social media ban.
It is clear from the ruling that by including YouTube, Reddit and Facebook, they take a broad definition of what social media is, essentially anything with user interaction and Hacker News definitely fits the bill.
And if your criteria includes "social aspects like user profiles and followers", then GitHub would fit too: it has user profiles, followers / stars, and allows for discussion. It is even included in the "social media" list for ESTA and visa applications for the US. We could even include StackOverflow, I mean, it used to be common practice to build a profile, chasing a reputation score so that you could show off to recruiters.
Originally it wasn't. It was more similar to hackernews, just more general. Lately it's going all in on wanting to be a social media platform full of dark design patterns to keep people hooked. Hackernews has barely changed from its beginning. I don't feel overwhelmed browsing it. Five minutes of reddit and I fall into a dopamine hole that can be hard to get out of. It's no longer part of my daily routine for that reason.
You can't follow people or have followers. There's no notification system when someone "likes" your comment. It doesn't lend itself towards pulling you back with the latest comment or post. There is the front page algorithm, but you can always just go to /latest or /active. It's about the content, not the users.
Critically, there's no ads or monetization (which is where all that garbage comes in).
HN is an anti-social media. It is not inclusive. If you are not a tech geek or cannot articulate well you are not welcome here, and will be ignored.
You cannot follow or be followed. There is no attention drawn to your username or profile. Everything about HN is designed for you to just read a comment and move on, not caring much about the human behind it.